This report has the objective to functions that can be used on R Studio. The chosen dataset is a list of various body measurements of men and the percentage of body fat, based on estimative using body density.

It has been proven that the measurements of various body circumferences can be used to estimate the percentage of body fat, without any other method. This is extremely useful for people or professional because there is no cost to estimate it.

This dataset is highly recommended for classes and linear regression, therefore, the data would fit perfectly to the purpose of this report. The source was http://lib.stat.cmu.edu/datasets/bodyfat and because it was in a txt file, the data needed to be separated, collated in a spreadsheet and saved as csv file.

The variables are integers and continuous. They are listed below: Body Density, Percent of Body Fat, Age (years), Weight (lbs), Height (inches), Neck circumference (cm), Chest circumference (cm), Abdomen circumference (cm), Hip circumference (cm), Thigh circumference (cm), Knee circumference (cm), Ankle circumference (cm), Biceps (extended) circumference (cm), Forearm circumference (cm) e Wrist circumference (cm).

Firstly, the working directory needs to be choosen:

setwd("D:/UTS/36103 - Statistical Thinking for Data Science/Assign_36103_09032015")

Then the dataset needs to be imported. The dataset has been named as “body”.

body <- read.csv("D:/UTS/36103 - Statistical Thinking for Data Science/Assign_36103_09032015/body.csv")

It’s important to check the dataset and make sure there is no evident discrepancies.Any check need to be done because this dataset has been used previously. All variables and attributes can be seen below:

body
##     bodydensity bodyfat age weight height neck chest abdomen   hip thigh
## 1        1.0708    12.3  23 154.25  67.75 36.2  93.1    85.2  94.5  59.0
## 2        1.0853     6.1  22 173.25  72.25 38.5  93.6    83.0  98.7  58.7
## 3        1.0414    25.3  22 154.00  66.25 34.0  95.8    87.9  99.2  59.6
## 4        1.0751    10.4  26 184.75  72.25 37.4 101.8    86.4 101.2  60.1
## 5        1.0340    28.7  24 184.25  71.25 34.4  97.3   100.0 101.9  63.2
## 6        1.0502    20.9  24 210.25  74.75 39.0 104.5    94.4 107.8  66.0
## 7        1.0549    19.2  26 181.00  69.75 36.4 105.1    90.7 100.3  58.4
## 8        1.0704    12.4  25 176.00  72.50 37.8  99.6    88.5  97.1  60.0
## 9        1.0900     4.1  25 191.00  74.00 38.1 100.9    82.5  99.9  62.9
## 10       1.0722    11.7  23 198.25  73.50 42.1  99.6    88.6 104.1  63.1
## 11       1.0830     7.1  26 186.25  74.50 38.5 101.5    83.6  98.2  59.7
## 12       1.0812     7.8  27 216.00  76.00 39.4 103.6    90.9 107.7  66.2
## 13       1.0513    20.8  32 180.50  69.50 38.4 102.0    91.6 103.9  63.4
## 14       1.0505    21.2  30 205.25  71.25 39.4 104.1   101.8 108.6  66.0
## 15       1.0484    22.1  35 187.75  69.50 40.5 101.3    96.4 100.1  69.0
## 16       1.0512    20.9  35 162.75  66.00 36.4  99.1    92.8  99.2  63.1
## 17       1.0333    29.0  34 195.75  71.00 38.9 101.9    96.4 105.2  64.8
## 18       1.0468    22.9  32 209.25  71.00 42.1 107.6    97.5 107.0  66.9
## 19       1.0622    16.0  28 183.75  67.75 38.0 106.8    89.6 102.4  64.2
## 20       1.0610    16.5  33 211.75  73.50 40.0 106.2   100.5 109.0  65.8
## 21       1.0551    19.1  28 179.00  68.00 39.1 103.3    95.9 104.9  63.5
## 22       1.0640    15.2  28 200.50  69.75 41.3 111.4    98.8 104.8  63.4
## 23       1.0631    15.6  31 140.25  68.25 33.9  86.0    76.4  94.6  57.4
## 24       1.0584    17.7  32 148.75  70.00 35.5  86.7    80.0  93.4  54.9
## 25       1.0668    14.0  28 151.25  67.75 34.5  90.2    76.3  95.8  58.4
## 26       1.0911     3.7  27 159.25  71.50 35.7  89.6    79.7  96.5  55.0
## 27       1.0811     7.9  34 131.50  67.50 36.2  88.6    74.6  85.3  51.7
## 28       1.0468    22.9  31 148.00  67.50 38.8  97.4    88.7  94.7  57.5
## 29       1.0910     3.7  27 133.25  64.75 36.4  93.5    73.9  88.5  50.1
## 30       1.0790     8.8  29 160.75  69.00 36.7  97.4    83.5  98.7  58.9
## 31       1.0716    11.9  32 182.00  73.75 38.7 100.5    88.7  99.8  57.5
## 32       1.0862     5.7  29 160.25  71.25 37.3  93.5    84.5 100.6  58.5
## 33       1.0719    11.8  27 168.00  71.25 38.1  93.0    79.1  94.5  57.3
## 34       1.0502    21.3  41 218.50  71.00 39.8 111.7   100.5 108.3  67.1
## 35       1.0263    32.3  41 247.25  73.50 42.1 117.0   115.6 116.1  71.2
## 36       1.0101    40.1  49 191.75  65.00 38.4 118.5   113.1 113.8  61.9
## 37       1.0438    24.2  40 202.25  70.00 38.5 106.5   100.9 106.2  63.5
## 38       1.0346    28.4  50 196.75  68.25 42.1 105.6    98.8 104.8  66.0
## 39       1.0202    35.2  46 363.15  72.25 51.2 136.2   148.1 147.7  87.3
## 40       1.0258    32.6  50 203.00  67.00 40.2 114.8   108.1 102.5  61.3
## 41       1.0217    34.5  45 262.75  68.75 43.2 128.3   126.2 125.6  72.5
## 42       1.0250    32.9  44 205.00  29.50 36.6 106.0   104.3 115.5  70.6
## 43       1.0279    31.6  48 217.00  70.00 37.3 113.3   111.2 114.1  67.7
## 44       1.0269    32.0  41 212.00  71.50 41.5 106.6   104.3 106.0  65.0
## 45       1.0814     7.7  39 125.25  68.00 31.5  85.1    76.0  88.2  50.0
## 46       1.0670    13.9  43 164.25  73.25 35.7  96.6    81.5  97.2  58.4
## 47       1.0742    10.8  40 133.50  67.50 33.6  88.2    73.7  88.5  53.3
## 48       1.0665     5.6  39 148.50  71.25 34.6  89.8    79.5  92.7  52.7
## 49       1.0678    13.6  45 135.75  68.50 32.8  92.3    83.4  90.4  52.0
## 50       1.0903     4.0  47 127.50  66.75 34.0  83.4    70.4  87.2  50.6
## 51       1.0756    10.2  47 158.25  72.25 34.9  90.2    86.7  98.3  52.6
## 52       1.0840     6.6  40 139.25  69.00 34.3  89.2    77.9  91.0  51.4
## 53       1.0807     8.0  51 137.25  67.75 36.5  89.7    82.0  89.1  49.3
## 54       1.0848     6.3  49 152.75  73.50 35.1  93.3    79.6  91.6  52.6
## 55       1.0906     3.9  42 136.25  67.50 37.8  87.6    77.6  88.6  51.9
## 56       1.0473    22.6  54 198.00  72.00 39.9 107.6   100.0  99.6  57.2
## 57       1.0524    20.4  58 181.50  68.00 39.1 100.0    99.8 102.5  62.1
## 58       1.0356    28.0  62 201.25  69.50 40.5 111.5   104.2 105.8  61.8
## 59       1.0280    31.5  54 202.50  70.75 40.5 115.4   105.3  97.0  59.1
## 60       1.0430    24.6  61 179.75  65.75 38.4 104.8    98.3  99.6  60.6
## 61       1.0396    26.1  62 216.00  73.25 41.4 112.3   104.8 103.1  61.6
## 62       1.0317    29.8  56 178.75  68.50 35.6 102.9    94.7 100.8  60.9
## 63       1.0298    30.7  54 193.25  70.25 38.0 107.6   102.4  99.4  61.0
## 64       1.0403    25.8  61 178.00  67.00 37.4 105.3    99.7  99.7  60.8
## 65       1.0264    32.3  57 205.50  70.00 40.1 105.3   105.5 108.3  65.0
## 66       1.0313    30.0  55 183.50  67.50 40.9 103.0   100.3 104.2  64.8
## 67       1.0499    21.5  54 151.50  70.75 35.6  90.0    83.9  93.9  55.0
## 68       1.0673    13.8  55 154.75  71.50 36.9  95.4    86.6  91.8  54.3
## 69       1.0847     6.3  54 155.25  69.25 37.5  89.3    78.4  96.1  56.0
## 70       1.0693    12.9  55 156.75  71.50 36.3  94.4    84.6  94.3  51.2
## 71       1.0439    24.3  62 167.50  71.50 35.5  97.6    91.5  98.5  56.6
## 72       1.0788     8.8  55 146.75  68.75 38.7  88.5    82.8  95.5  58.9
## 73       1.0796     8.5  56 160.75  73.75 36.4  93.6    82.9  96.3  52.9
## 74       1.0680    13.5  55 125.00  64.00 33.2  87.7    76.0  88.6  50.9
## 75       1.0720    11.8  61 143.00  65.75 36.5  93.4    83.3  93.0  55.5
## 76       1.0666    18.5  61 148.25  67.50 36.0  91.6    81.8  94.8  54.5
## 77       1.0790     8.8  57 162.50  69.50 38.7  91.6    78.8  94.3  56.7
## 78       1.0483    22.2  69 177.75  68.50 38.7 102.0    95.0  98.3  55.0
## 79       1.0498    21.5  81 161.25  70.25 37.8  96.4    95.4  99.3  53.5
## 80       1.0560    18.8  66 171.25  69.25 37.4 102.7    98.6 100.2  56.5
## 81       1.0283    31.4  67 163.75  67.75 38.4  97.7    95.8  97.1  54.8
## 82       1.0382    26.8  64 150.25  67.25 38.1  97.1    89.0  96.9  54.8
## 83       1.0568    18.4  64 190.25  72.75 39.3 103.1    97.8  99.6  58.9
## 84       1.0377    27.0  70 170.75  70.00 38.7 101.8    94.9  95.0  56.0
## 85       1.0378    27.0  72 168.00  69.25 38.5 101.4    99.8  96.2  56.3
## 86       1.0386    26.6  67 167.00  67.50 36.5  98.9    89.7  96.2  54.7
## 87       1.0648    14.9  72 157.75  67.25 37.7  97.5    88.1  96.9  57.2
## 88       1.0462    23.1  64 160.00  65.75 36.5 104.3    90.9  93.8  57.8
## 89       1.0800     8.3  46 176.75  72.50 38.0  97.3    86.0  99.3  61.0
## 90       1.0666    14.1  48 176.00  73.00 36.7  96.7    86.5  98.3  60.4
## 91       1.0520    20.5  46 177.00  70.00 37.2  99.7    95.6 102.2  58.3
## 92       1.0573    18.2  44 179.75  69.50 39.2 101.9    93.2 100.6  58.9
## 93       1.0795     8.5  47 165.25  70.50 37.5  97.2    83.1  95.4  56.9
## 94       1.0424    24.9  46 192.50  71.75 38.0 106.6    97.5 100.6  58.9
## 95       1.0785     9.0  47 184.25  74.50 37.3  99.6    88.8 101.4  57.4
## 96       1.0991    17.4  53 224.50  77.75 41.1 113.2    99.2 107.5  61.7
## 97       1.0770     9.6  38 188.75  73.25 37.5  99.1    91.6 102.4  60.6
## 98       1.0730    11.3  50 162.50  66.50 38.7  99.4    86.7  96.2  62.1
## 99       1.0582    17.8  46 156.50  68.25 35.9  95.1    88.2  92.8  54.7
## 100      1.0484    22.2  47 197.00  72.00 40.0 107.5    94.0 103.7  62.7
## 101      1.0506    21.2  49 198.50  73.50 40.1 106.5    95.0 101.7  59.0
## 102      1.0524    20.4  48 173.75  72.00 37.0  99.1    92.0  98.3  59.3
## 103      1.0530    20.1  41 172.75  71.25 36.3  96.7    89.2  98.3  60.0
## 104      1.0480    22.3  49 196.75  73.75 40.7 103.5    95.5 101.6  59.1
## 105      1.0412    25.4  43 177.00  69.25 39.6 104.0    98.6  99.5  59.5
## 106      1.0578    18.0  43 165.50  68.50 31.1  93.1    87.3  96.6  54.7
## 107      1.0547    19.3  43 200.25  73.50 38.6 105.2   102.8 103.6  61.2
## 108      1.0569    18.3  52 203.25  74.25 42.0 110.0   101.6 100.7  55.8
## 109      1.0593    17.3  43 194.00  75.50 38.5 110.1    88.7 102.1  57.5
## 110      1.0500    21.4  40 168.50  69.25 34.2  97.8    92.3 100.6  57.5
## 111      1.0538    19.7  43 170.75  68.50 37.2  96.3    90.6  99.3  61.9
## 112      1.0355    28.0  43 183.25  70.00 37.1 108.0   105.0 103.0  63.7
## 113      1.0486    22.1  47 178.25  70.00 40.2  99.7    95.0  98.6  62.3
## 114      1.0503    21.3  42 163.00  70.25 35.3  93.5    89.6  99.8  61.5
## 115      1.0384    26.7  48 175.25  71.75 38.0 100.7    92.4  97.5  59.3
## 116      1.0607    16.7  40 158.00  69.25 36.3  97.0    86.6  92.6  55.9
## 117      1.0529    20.1  48 177.25  72.75 36.8  96.0    90.0  99.7  58.8
## 118      1.0671    13.9  51 179.00  72.00 41.0  99.2    90.0  96.4  56.8
## 119      1.0404    25.8  40 191.00  74.00 38.3  95.4    92.4 104.3  64.6
## 120      1.0575    18.1  44 187.50  72.25 38.0 101.8    87.5 101.0  58.5
## 121      1.0358    27.9  52 206.50  74.50 40.8 104.3    99.2 104.1  58.5
## 122      1.0414    25.3  44 185.25  71.50 39.5  99.2    98.1 101.4  57.1
## 123      1.0652    14.7  40 160.25  68.75 36.9  99.3    83.3  97.5  60.5
## 124      1.0623    16.0  47 151.50  66.75 36.9  94.0    86.1  95.2  58.1
## 125      1.0674    13.8  50 161.00  66.50 37.7  98.9    84.1  94.0  58.5
## 126      1.0587    17.5  46 167.00  67.00 36.6 101.0    89.9 100.0  60.7
## 127      1.0373    27.2  42 177.50  68.75 38.9  98.7    92.1  98.5  60.7
## 128      1.0590    17.4  43 152.25  67.75 37.5  95.9    78.0  93.2  53.5
## 129      1.0515    20.8  40 192.25  73.25 39.8 103.9    93.5  99.5  61.7
## 130      1.0648    14.9  42 165.25  69.75 38.3  96.2    87.0  97.8  57.4
## 131      1.0575    18.1  49 171.75  71.50 35.5  97.8    90.1  95.8  57.0
## 132      1.0472    22.7  40 171.25  70.50 36.3  94.6    90.3  99.1  60.3
## 133      1.0452    23.6  47 197.00  73.25 37.8 103.6    99.8 103.2  61.2
## 134      1.0398    26.1  50 157.00  66.75 37.8 100.4    89.4  92.3  56.1
## 135      1.0435    24.4  41 168.25  69.50 36.5  98.4    87.2  98.4  56.0
## 136      1.0374    27.1  44 186.00  69.75 37.8 104.6   101.1 102.1  58.9
## 137      1.0491    21.8  39 166.75  70.75 37.0  92.9    86.1  95.6  58.8
## 138      1.0325    29.4  43 187.75  74.00 37.7  97.8    98.6 100.6  63.6
## 139      1.0481    22.4  40 168.25  71.25 34.3  98.3    88.5  98.3  58.1
## 140      1.0522    20.4  49 212.75  75.00 40.8 104.7   106.6 107.7  66.5
## 141      1.0422    24.9  40 176.75  71.00 37.4  98.6    93.1 101.6  59.1
## 142      1.0571    18.3  40 173.25  69.50 36.5  99.5    93.0  99.3  60.4
## 143      1.0459    23.3  52 167.00  67.75 37.5 102.7    91.0  98.9  57.1
## 144      1.0775     9.4  23 159.75  72.25 35.5  92.1    77.1  93.9  56.1
## 145      1.0754    10.3  23 188.15  77.50 38.0  96.6    85.3 102.5  59.1
## 146      1.0664    14.2  24 156.00  70.75 35.7  92.7    81.9  95.3  56.4
## 147      1.0550    19.2  24 208.50  72.75 39.2 102.0    99.1 110.1  71.2
## 148      1.0322    29.6  25 206.50  69.75 40.9 110.9   100.5 106.2  68.4
## 149      1.0873     5.3  25 143.75  72.50 35.2  92.3    76.5  92.1  51.9
## 150      1.0416    25.2  26 223.00  70.25 40.6 114.1   106.8 113.9  67.6
## 151      1.0776     9.4  26 152.25  69.00 35.4  92.9    77.6  93.5  56.9
## 152      1.0542    19.6  26 241.75  74.50 41.8 108.3   102.9 114.4  72.9
## 153      1.0758    10.1  27 146.00  72.25 34.1  88.5    72.8  91.1  53.6
## 154      1.0610    16.5  27 156.75  67.25 37.9  94.0    88.2  95.2  56.8
## 155      1.0510    21.0  27 200.25  73.50 38.2 101.1   100.1 105.0  62.1
## 156      1.0594    17.3  28 171.50  75.25 35.6  92.1    83.5  98.3  57.3
## 157      1.0287    31.2  28 205.75  69.00 38.5 105.6   105.0 106.4  68.6
## 158      1.0761    10.0  28 182.50  72.25 37.0  98.5    90.8 102.5  60.8
## 159      1.0704    12.5  30 136.50  68.75 35.9  88.7    76.6  89.8  50.1
## 160      1.0477    22.5  31 177.25  71.50 36.2 101.1    92.4  99.3  59.4
## 161      1.0775     9.4  31 151.25  72.25 35.0  94.0    81.2  91.5  52.5
## 162      1.0653    14.6  33 196.00  73.00 38.5 103.8    95.6 105.1  61.4
## 163      1.0690    13.0  33 184.25  68.75 40.7  98.9    92.1 103.5  64.0
## 164      1.0644    15.1  34 140.00  70.50 36.0  89.2    83.4  89.6  52.4
## 165      1.0370    27.3  34 218.75  72.00 39.5 111.4   106.0 108.8  63.8
## 166      1.0549    19.2  35 217.00  73.75 40.5 107.5    95.1 104.5  64.8
## 167      1.0492    21.8  35 166.25  68.00 38.5  99.1    90.4  95.6  55.5
## 168      1.0525    20.3  35 224.75  72.25 43.9 108.2   100.4 106.8  63.3
## 169      1.0180    34.3  35 228.25  69.50 40.4 114.9   115.9 111.9  74.4
## 170      1.0610    16.5  35 172.75  69.50 37.6  99.1    90.8  98.1  60.1
## 171      1.0926     3.0  35 152.25  67.75 37.0  92.2    81.9  92.8  54.7
## 172      1.0983     0.7  35 125.75  65.50 34.0  90.8    75.0  89.2  50.0
## 173      1.0521    20.5  35 177.25  71.00 38.4 100.5    90.3  98.7  57.8
## 174      1.0603    16.9  36 176.25  71.50 38.7  98.2    90.3  99.9  59.2
## 175      1.0414    25.3  36 226.75  71.75 41.5 115.3   108.8 114.4  69.2
## 176      1.0763     9.9  37 145.25  69.25 36.0  96.8    79.4  89.2  50.3
## 177      1.0689    13.1  37 151.00  67.00 35.3  92.6    83.2  96.4  60.0
## 178      1.0316    29.9  37 241.25  71.50 42.1 119.2   110.3 113.9  69.8
## 179      1.0477    22.5  38 187.25  69.25 38.0 102.7    92.7 101.9  64.7
## 180      1.0603    16.9  39 234.75  74.50 42.8 109.5   104.5 109.9  69.5
## 181      1.0387    26.6  39 219.25  74.25 40.0 108.5   104.6 109.8  68.1
## 182      1.1089     0.0  40 118.50  68.00 33.8  79.3    69.4  85.0  47.2
## 183      1.0725    11.5  40 145.75  67.25 35.5  95.5    83.6  91.6  54.1
## 184      1.0713    12.1  40 159.25  69.75 35.3  92.3    86.8  96.1  58.0
## 185      1.0587    17.5  40 170.50  74.25 37.7  98.9    90.4  95.5  55.4
## 186      1.0794     8.6  40 167.50  71.50 39.4  89.5    83.7  98.1  57.3
## 187      1.0453    23.6  41 232.75  74.25 41.9 117.5   109.3 108.8  67.7
## 188      1.0524    20.4  41 210.50  72.00 38.5 107.4    98.9 104.1  63.5
## 189      1.0520    20.5  41 202.25  72.50 40.8 109.2    98.0 101.8  62.8
## 190      1.0434    24.4  41 185.00  68.25 38.0 103.4   101.2 103.1  61.5
## 191      1.0728    11.4  41 153.00  69.25 36.4  91.4    80.6  92.3  54.3
## 192      1.0140    38.1  42 244.25  76.00 41.8 115.2   113.7 112.4  68.5
## 193      1.0624    15.9  42 193.50  70.50 40.7 104.9    94.1 102.7  60.6
## 194      1.0429    24.7  42 224.75  74.75 38.5 106.7   105.7 111.8  65.3
## 195      1.0470    22.8  42 162.75  72.75 35.4  92.2    85.6  96.5  60.2
## 196      1.0411    25.5  42 180.00  68.25 38.5 101.6    96.6 100.6  61.1
## 197      1.0488    22.0  42 156.25  69.00 35.5  97.8    86.0  96.2  57.7
## 198      1.0583    17.7  42 168.00  71.50 36.5  92.0    89.7 101.0  62.3
## 199      1.0841     6.6  42 167.25  72.75 37.6  94.0    78.0  99.0  57.5
## 200      1.0462    23.6  43 170.75  67.50 37.4 103.7    89.7  94.2  58.5
## 201      1.0709    12.2  43 178.25  70.25 37.8 102.7    89.2  99.2  60.2
## 202      1.0484    22.1  43 150.00  69.25 35.2  91.1    85.7  96.9  55.5
## 203      1.0340    28.7  43 200.50  71.50 37.9 107.2   103.1 105.5  68.8
## 204      1.0854     6.0  44 184.00  74.00 37.9 100.8    89.1 102.6  60.6
## 205      1.0209    34.8  44 223.00  69.75 40.9 121.6   113.9 107.1  63.5
## 206      1.0610    16.6  44 208.75  73.00 41.9 105.6    96.3 102.0  63.3
## 207      1.0250    32.9  44 166.00  65.50 39.1 100.6    93.9 100.1  58.9
## 208      1.0254    32.8  47 195.00  72.50 40.2 102.7   101.3 101.7  60.7
## 209      1.0771     9.6  47 160.50  70.25 36.0  99.8    83.9  91.8  53.0
## 210      1.0742    10.8  47 159.75  70.75 34.5  92.9    84.4  94.0  56.0
## 211      1.0829     7.1  49 140.50  68.00 35.8  91.2    79.4  89.0  51.1
## 212      1.0373    27.2  49 216.25  74.50 40.2 115.6   104.0 109.0  63.7
## 213      1.0543    19.5  49 168.25  71.75 38.3  98.3    89.7  99.1  56.3
## 214      1.0561    18.7  50 194.75  70.75 39.0 103.7    97.6 104.2  60.0
## 215      1.0543    19.5  50 172.75  73.00 37.4  98.7    87.6  96.1  57.1
## 216      0.9950    47.5  51 219.00  64.00 41.2 119.8   122.1 112.8  62.5
## 217      1.0678    13.6  51 149.25  69.75 34.8  92.8    81.1  96.3  53.8
## 218      1.0819     7.5  51 154.50  70.00 36.9  93.3    81.5  94.4  54.7
## 219      1.0433    24.5  52 199.25  71.75 39.4 106.8   100.0 105.0  63.9
## 220      1.0646    15.0  53 154.50  69.25 37.6  93.9    88.7  94.5  53.7
## 221      1.0706    12.4  54 153.25  70.50 38.5  99.0    91.8  96.2  57.7
## 222      1.0399    26.0  54 230.00  72.25 42.5 119.9   110.4 105.5  64.2
## 223      1.0726    11.5  54 161.75  67.50 37.4  94.2    87.6  95.6  59.7
## 224      1.0874     5.2  55 142.25  67.25 35.2  92.7    82.8  91.9  54.4
## 225      1.0740    10.9  55 179.75  68.75 41.1 106.9    95.3  98.2  57.4
## 226      1.0703    12.5  55 126.50  66.75 33.4  88.8    78.2  87.5  50.8
## 227      1.0650    14.8  55 169.50  68.25 37.2 101.7    91.1  97.1  56.6
## 228      1.0418    25.2  55 198.50  74.25 38.3 105.3    96.7 106.6  64.0
## 229      1.0647    14.9  56 174.50  69.50 38.1 104.0    89.4  98.4  58.4
## 230      1.0601    17.0  56 167.75  68.50 37.4  98.6    93.0  97.0  55.4
## 231      1.0745    10.6  57 147.75  65.75 35.2  99.6    86.4  90.1  53.0
## 232      1.0620    16.1  57 182.25  71.75 39.4 103.4    96.7 100.7  59.3
## 233      1.0636    15.4  58 175.50  71.50 38.0 100.2    88.1  97.8  57.1
## 234      1.0384    26.7  58 161.75  67.25 35.1  94.9    94.9 100.2  56.8
## 235      1.0403    25.8  60 157.75  67.50 40.4  97.2    93.3  94.0  54.3
## 236      1.0563    18.6  62 168.75  67.50 38.3 104.7    95.6  93.7  54.4
## 237      1.0424    24.8  62 191.50  72.25 40.6 104.0    98.2 101.1  59.3
## 238      1.0372    27.3  63 219.15  69.50 40.2 117.6   113.8 111.8  63.4
## 239      1.0705    12.4  64 155.25  69.50 37.9  95.8    82.8  94.5  61.2
## 240      1.0316    29.9  65 189.75  65.75 40.8 106.4   100.5 100.5  59.2
## 241      1.0599    17.0  65 127.50  65.75 34.7  93.0    79.7  87.6  50.7
## 242      1.0207    35.0  65 224.50  68.25 38.8 119.6   118.0 114.3  61.3
## 243      1.0304    30.4  66 234.25  72.00 41.4 119.7   109.0 109.1  63.7
## 244      1.0256    32.6  67 227.75  72.75 41.3 115.8   113.4 109.8  65.6
## 245      1.0334    29.0  67 199.50  68.50 40.7 118.3   106.1 101.6  58.2
## 246      1.0641    15.2  68 155.50  69.25 36.3  97.4    84.3  94.4  54.3
## 247      1.0308    30.2  69 215.50  70.50 40.8 113.7   107.6 110.0  63.3
## 248      1.0736    11.0  70 134.25  67.00 34.9  89.2    83.6  88.8  49.6
## 249      1.0236    33.6  72 201.00  69.75 40.9 108.5   105.0 104.5  59.6
## 250      1.0328    29.3  72 186.75  66.00 38.9 111.1   111.5 101.7  60.3
## 251      1.0399    26.0  72 190.75  70.50 38.9 108.3   101.3  97.8  56.0
## 252      1.0271    31.9  74 207.50  70.00 40.8 112.4   108.5 107.1  59.3
##     knee ankle biceps forearm wrist
## 1   37.3  21.9   32.0    27.4  17.1
## 2   37.3  23.4   30.5    28.9  18.2
## 3   38.9  24.0   28.8    25.2  16.6
## 4   37.3  22.8   32.4    29.4  18.2
## 5   42.2  24.0   32.2    27.7  17.7
## 6   42.0  25.6   35.7    30.6  18.8
## 7   38.3  22.9   31.9    27.8  17.7
## 8   39.4  23.2   30.5    29.0  18.8
## 9   38.3  23.8   35.9    31.1  18.2
## 10  41.7  25.0   35.6    30.0  19.2
## 11  39.7  25.2   32.8    29.4  18.5
## 12  39.2  25.9   37.2    30.2  19.0
## 13  38.3  21.5   32.5    28.6  17.7
## 14  41.5  23.7   36.9    31.6  18.8
## 15  39.0  23.1   36.1    30.5  18.2
## 16  38.7  21.7   31.1    26.4  16.9
## 17  40.8  23.1   36.2    30.8  17.3
## 18  40.0  24.4   38.2    31.6  19.3
## 19  38.7  22.9   37.2    30.5  18.5
## 20  40.6  24.0   37.1    30.1  18.2
## 21  38.0  22.1   32.5    30.3  18.4
## 22  40.6  24.6   33.0    32.8  19.9
## 23  35.3  22.2   27.9    25.9  16.7
## 24  36.2  22.1   29.8    26.7  17.1
## 25  35.5  22.9   31.1    28.0  17.6
## 26  36.7  22.5   29.9    28.2  17.7
## 27  34.7  21.4   28.7    27.0  16.5
## 28  36.0  21.0   29.2    26.6  17.0
## 29  34.5  21.3   30.5    27.9  17.2
## 30  35.3  22.6   30.1    26.7  17.6
## 31  38.7  33.9   32.5    27.7  18.4
## 32  38.8  21.5   30.1    26.4  17.9
## 33  36.2  24.5   29.0    30.0  18.8
## 34  44.2  25.2   37.5    31.5  18.7
## 35  43.3  26.3   37.3    31.7  19.7
## 36  38.3  21.9   32.0    29.8  17.0
## 37  39.9  22.6   35.1    30.6  19.0
## 38  41.5  24.7   33.2    30.5  19.4
## 39  49.1  29.6   45.0    29.0  21.4
## 40  41.1  24.7   34.1    31.0  18.3
## 41  39.6  26.6   36.4    32.7  21.4
## 42  42.5  23.7   33.6    28.7  17.4
## 43  40.9  25.0   36.7    29.8  18.4
## 44  40.2  23.0   35.8    31.5  18.8
## 45  34.7  21.0   26.1    23.1  16.1
## 46  38.2  23.4   29.7    27.4  18.3
## 47  34.5  22.5   27.9    26.2  17.3
## 48  37.5  21.9   28.8    26.8  17.9
## 49  35.8  20.6   28.8    25.5  16.3
## 50  34.4  21.9   26.8    25.8  16.8
## 51  37.2  22.4   26.0    25.8  17.3
## 52  34.9  21.0   26.7    26.1  17.2
## 53  33.7  21.4   29.6    26.0  16.9
## 54  37.6  22.6   38.5    27.4  18.5
## 55  34.9  22.5   27.7    27.5  18.5
## 56  38.0  22.0   35.9    30.2  18.9
## 57  39.6  22.5   33.1    28.3  18.5
## 58  39.8  22.7   37.7    30.9  19.2
## 59  38.0  22.5   31.6    28.8  18.2
## 60  37.7  22.9   34.5    29.6  18.5
## 61  40.9  23.1   36.2    31.8  20.2
## 62  38.0  22.1   32.5    29.8  18.3
## 63  39.4  23.6   32.7    29.9  19.1
## 64  40.1  22.7   33.6    29.0  18.8
## 65  41.2  24.7   35.3    31.1  18.4
## 66  40.2  22.7   34.8    30.1  18.7
## 67  36.1  21.7   29.6    27.4  17.4
## 68  35.4  21.5   32.8    27.4  18.7
## 69  37.4  22.4   32.6    28.1  18.1
## 70  37.4  21.6   27.3    27.1  17.3
## 71  38.6  22.4   31.5    27.3  18.6
## 72  37.6  21.6   30.3    27.3  18.3
## 73  37.5  23.1   29.7    27.3  18.2
## 74  35.4  19.1   29.3    25.7  16.9
## 75  35.2  20.9   29.4    27.0  16.8
## 76  37.0  21.4   29.3    27.0  18.3
## 77  39.7  24.2   30.2    29.2  18.1
## 78  38.3  21.8   30.8    25.7  18.8
## 79  37.5  21.5   31.4    26.8  18.3
## 80  39.3  22.7   30.3    28.7  19.0
## 81  38.2  23.7   29.4    27.2  19.0
## 82  38.0  22.0   29.9    25.2  17.7
## 83  39.0  23.0   34.3    29.6  19.0
## 84  36.5  24.1   31.2    27.3  19.2
## 85  36.6  22.0   29.7    26.3  18.0
## 86  37.8  33.7   32.4    27.7  18.2
## 87  37.7  21.8   32.6    28.0  18.8
## 88  39.5  23.3   29.2    28.4  18.1
## 89  38.4  23.8   30.2    29.3  18.8
## 90  39.9  24.4   28.8    29.6  18.7
## 91  38.2  22.5   29.1    27.7  17.7
## 92  39.7  23.1   31.4    28.4  18.8
## 93  38.3  22.1   30.1    28.2  18.4
## 94  40.5  24.5   33.3    29.6  19.1
## 95  39.6  24.6   30.3    27.9  17.8
## 96  42.3  23.2   32.9    30.8  20.4
## 97  39.4  22.9   31.6    30.1  18.5
## 98  39.3  23.3   30.6    27.8  18.2
## 99  37.3  21.9   31.6    27.5  18.2
## 100 39.0  22.3   35.3    30.9  18.3
## 101 39.4  22.3   32.2    31.0  18.6
## 102 38.4  22.4   27.9    26.2  17.0
## 103 38.4  23.2   31.0    29.2  18.4
## 104 39.8  25.4   31.0    30.3  19.7
## 105 36.1  22.0   30.1    27.2  17.7
## 106 39.0  24.8   31.0    29.4  18.8
## 107 39.3  23.5   30.5    28.5  18.1
## 108 38.7  23.4   35.1    29.6  19.1
## 109 40.0  24.8   35.1    30.7  19.2
## 110 36.8  22.8   32.1    26.0  17.3
## 111 38.0  22.3   33.3    28.2  18.1
## 112 40.0  23.6   33.5    27.8  17.4
## 113 38.1  23.9   35.3    31.1  19.8
## 114 37.8  21.9   30.7    27.6  17.4
## 115 38.1  21.8   31.8    27.3  17.5
## 116 36.3  22.1   29.8    26.3  17.3
## 117 38.4  22.8   29.9    28.0  18.1
## 118 38.8  23.3   33.4    29.8  19.5
## 119 41.1  24.8   33.6    29.5  18.5
## 120 39.2  24.5   32.1    28.6  18.0
## 121 39.3  24.6   33.9    31.2  19.5
## 122 40.5  23.2   33.0    29.6  18.4
## 123 38.7  22.6   34.4    28.0  17.6
## 124 36.5  22.1   30.6    27.5  17.6
## 125 36.6  23.5   34.4    29.2  18.0
## 126 36.0  21.9   35.6    30.2  17.6
## 127 36.8  22.2   33.8    30.3  17.2
## 128 35.8  20.8   33.9    28.2  17.4
## 129 39.0  21.8   33.3    29.6  18.1
## 130 36.9  22.2   31.6    27.8  17.7
## 131 38.7  23.2   27.5    26.5  17.6
## 132 38.5  23.0   31.2    28.4  17.1
## 133 38.1  22.6   33.5    28.6  17.9
## 134 35.6  20.5   33.6    29.3  17.3
## 135 36.9  23.0   34.0    29.8  18.1
## 136 37.9  22.7   30.9    28.8  17.6
## 137 36.1  22.4   32.7    28.3  17.1
## 138 39.2  23.8   34.3    28.4  17.7
## 139 38.4  22.5   31.7    27.4  17.6
## 140 42.5  24.5   35.5    29.8  18.7
## 141 39.6  21.6   30.8    27.9  16.6
## 142 38.2  22.0   32.0    28.5  17.8
## 143 36.7  22.3   31.6    27.5  17.9
## 144 36.1  22.7   30.5    27.2  18.2
## 145 37.6  23.2   31.8    29.7  18.3
## 146 36.5  22.0   33.5    28.3  17.3
## 147 43.5  25.2   36.1    30.3  18.7
## 148 40.8  24.6   33.3    29.7  18.4
## 149 35.7  22.0   25.8    25.2  16.9
## 150 42.7  24.7   36.0    30.4  18.4
## 151 35.9  20.4   31.6    29.0  17.8
## 152 43.5  25.1   38.5    33.8  19.6
## 153 36.8  23.8   27.8    26.3  17.4
## 154 37.4  22.8   30.6    28.3  17.9
## 155 40.0  24.9   33.7    29.2  19.4
## 156 37.8  21.7   32.2    27.7  17.7
## 157 40.0  25.2   35.2    30.7  19.1
## 158 38.5  25.0   31.6    28.0  18.6
## 159 34.8  21.8   27.0    34.9  16.9
## 160 39.0  24.6   30.1    28.2  18.2
## 161 36.6  21.0   27.0    26.3  16.5
## 162 40.6  25.0   31.3    29.2  19.1
## 163 37.3  23.5   33.5    30.6  19.7
## 164 35.6  20.4   28.3    26.2  16.5
## 165 42.0  23.4   34.0    31.2  18.5
## 166 41.3  25.6   36.4    33.7  19.4
## 167 34.2  21.9   30.2    28.7  17.7
## 168 41.7  24.6   37.2    33.1  19.8
## 169 40.6  24.0   36.1    31.8  18.8
## 170 39.1  23.4   32.5    29.8  17.4
## 171 36.2  22.1   30.4    27.4  17.7
## 172 34.8  22.0   24.8    25.9  16.9
## 173 37.3  22.4   31.0    28.7  17.7
## 174 37.7  21.5   32.4    28.4  17.8
## 175 42.4  24.0   35.4    21.0  20.1
## 176 34.8  22.2   31.0    26.9  16.9
## 177 38.1  22.0   31.5    26.6  16.7
## 178 42.6  24.8   34.4    29.5  18.4
## 179 39.5  24.7   34.8    30.3  18.1
## 180 43.1  25.8   39.1    32.5  19.9
## 181 42.8  24.1   35.6    29.0  19.0
## 182 33.5  20.2   27.7    24.6  16.5
## 183 36.2  21.8   31.4    28.3  17.2
## 184 39.4  22.7   30.0    26.4  17.4
## 185 38.9  22.4   30.5    28.9  17.7
## 186 39.7  22.6   32.9    29.3  18.2
## 187 41.3  24.7   37.2    31.8  20.0
## 188 39.8  23.5   36.4    30.4  19.1
## 189 41.3  24.8   36.6    32.4  18.8
## 190 40.4  22.9   33.4    29.2  18.5
## 191 36.3  21.8   29.6    27.3  17.9
## 192 45.0  25.5   37.1    31.2  19.9
## 193 38.6  24.7   34.0    30.1  18.7
## 194 43.3  26.0   33.7    29.9  18.5
## 195 38.9  22.4   31.7    27.1  17.1
## 196 38.4  24.1   32.9    29.8  18.8
## 197 38.6  24.0   31.2    27.3  17.4
## 198 38.0  22.3   30.8    27.8  16.9
## 199 40.0  22.5   30.6    30.0  18.5
## 200 39.0  24.1   33.8    28.8  18.8
## 201 39.2  23.8   31.7    28.4  18.6
## 202 35.7  22.0   29.4    26.6  17.4
## 203 38.3  23.7   32.1    28.9  18.7
## 204 39.0  24.0   32.9    29.2  18.4
## 205 40.3  21.8   34.8    30.7  17.4
## 206 39.8  24.1   37.3    23.1  19.4
## 207 37.6  21.4   33.1    29.5  17.3
## 208 39.4  23.3   36.7    31.6  18.4
## 209 36.2  22.5   31.4    27.5  17.7
## 210 38.2  22.6   29.0    26.2  17.6
## 211 35.0  21.7   30.9    28.8  17.4
## 212 40.3  23.2   36.8    31.0  18.9
## 213 38.8  23.0   29.5    27.9  18.6
## 214 40.9  25.5   32.7    30.0  19.0
## 215 38.1  21.8   28.6    26.7  18.0
## 216 36.9  23.6   34.7    29.1  18.4
## 217 36.5  21.5   31.3    26.3  17.8
## 218 39.0  22.6   27.5    25.9  18.6
## 219 39.2  22.9   35.7    30.4  19.2
## 220 36.2  22.0   28.5    25.7  17.1
## 221 38.1  23.9   31.4    29.9  18.9
## 222 42.7  27.0   38.4    32.0  19.6
## 223 40.2  23.4   27.9    27.0  17.8
## 224 35.2  22.5   29.4    26.8  17.0
## 225 37.1  21.8   34.1    31.1  19.2
## 226 33.0  19.7   25.3    22.0  15.8
## 227 38.5  22.6   33.4    29.3  18.8
## 228 42.6  23.4   33.2    30.0  18.4
## 229 37.4  22.5   34.6    30.1  18.8
## 230 38.8  23.2   32.4    29.7  19.0
## 231 35.0  21.3   31.7    27.3  16.9
## 232 38.6  22.8   31.8    29.1  19.0
## 233 38.9  23.6   30.9    29.6  18.0
## 234 35.9  21.0   27.8    26.1  17.6
## 235 35.7  21.0   31.3    28.7  18.3
## 236 37.1  22.7   30.3    26.3  18.3
## 237 40.3  23.0   32.6    28.5  19.0
## 238 41.1  22.3   35.1    29.6  18.5
## 239 39.1  22.3   29.8    28.9  18.3
## 240 38.1  24.0   35.9    30.5  19.1
## 241 33.4  20.1   28.5    24.8  16.5
## 242 42.1  23.4   34.9    30.1  19.4
## 243 42.4  24.6   35.6    30.7  19.5
## 244 46.0  25.4   35.3    29.8  19.5
## 245 38.8  24.1   32.1    29.3  18.5
## 246 37.5  22.6   29.2    27.3  18.5
## 247 44.0  22.6   37.5    32.6  18.8
## 248 34.8  21.5   25.6    25.7  18.5
## 249 40.8  23.2   35.2    28.6  20.1
## 250 37.3  21.5   31.3    27.2  18.0
## 251 41.6  22.7   30.5    29.4  19.8
## 252 42.2  24.6   33.7    30.0  20.9

And those are the descriptive statistics for the variables.

summary(body)
##   bodydensity       bodyfat           age            weight     
##  Min.   :0.995   Min.   : 0.00   Min.   :22.00   Min.   :118.5  
##  1st Qu.:1.041   1st Qu.:12.47   1st Qu.:35.75   1st Qu.:159.0  
##  Median :1.055   Median :19.20   Median :43.00   Median :176.5  
##  Mean   :1.056   Mean   :19.15   Mean   :44.88   Mean   :178.9  
##  3rd Qu.:1.070   3rd Qu.:25.30   3rd Qu.:54.00   3rd Qu.:197.0  
##  Max.   :1.109   Max.   :47.50   Max.   :81.00   Max.   :363.1  
##      height           neck           chest           abdomen      
##  Min.   :29.50   Min.   :31.10   Min.   : 79.30   Min.   : 69.40  
##  1st Qu.:68.25   1st Qu.:36.40   1st Qu.: 94.35   1st Qu.: 84.58  
##  Median :70.00   Median :38.00   Median : 99.65   Median : 90.95  
##  Mean   :70.15   Mean   :37.99   Mean   :100.82   Mean   : 92.56  
##  3rd Qu.:72.25   3rd Qu.:39.42   3rd Qu.:105.38   3rd Qu.: 99.33  
##  Max.   :77.75   Max.   :51.20   Max.   :136.20   Max.   :148.10  
##       hip            thigh            knee           ankle     
##  Min.   : 85.0   Min.   :47.20   Min.   :33.00   Min.   :19.1  
##  1st Qu.: 95.5   1st Qu.:56.00   1st Qu.:36.98   1st Qu.:22.0  
##  Median : 99.3   Median :59.00   Median :38.50   Median :22.8  
##  Mean   : 99.9   Mean   :59.41   Mean   :38.59   Mean   :23.1  
##  3rd Qu.:103.5   3rd Qu.:62.35   3rd Qu.:39.92   3rd Qu.:24.0  
##  Max.   :147.7   Max.   :87.30   Max.   :49.10   Max.   :33.9  
##      biceps         forearm          wrist      
##  Min.   :24.80   Min.   :21.00   Min.   :15.80  
##  1st Qu.:30.20   1st Qu.:27.30   1st Qu.:17.60  
##  Median :32.05   Median :28.70   Median :18.30  
##  Mean   :32.27   Mean   :28.66   Mean   :18.23  
##  3rd Qu.:34.33   3rd Qu.:30.00   3rd Qu.:18.80  
##  Max.   :45.00   Max.   :34.90   Max.   :21.40

The descriptive statistics for the first five variables:

summary(body[1:5])
##   bodydensity       bodyfat           age            weight     
##  Min.   :0.995   Min.   : 0.00   Min.   :22.00   Min.   :118.5  
##  1st Qu.:1.041   1st Qu.:12.47   1st Qu.:35.75   1st Qu.:159.0  
##  Median :1.055   Median :19.20   Median :43.00   Median :176.5  
##  Mean   :1.056   Mean   :19.15   Mean   :44.88   Mean   :178.9  
##  3rd Qu.:1.070   3rd Qu.:25.30   3rd Qu.:54.00   3rd Qu.:197.0  
##  Max.   :1.109   Max.   :47.50   Max.   :81.00   Max.   :363.1  
##      height     
##  Min.   :29.50  
##  1st Qu.:68.25  
##  Median :70.00  
##  Mean   :70.15  
##  3rd Qu.:72.25  
##  Max.   :77.75

A list of correlation for all variables are shown below, however only some variables show high correlation coefficients.

cor(body)
##             bodydensity     bodyfat         age      weight      height
## bodydensity  1.00000000 -0.98778240 -0.27763721 -0.59406188  0.09788114
## bodyfat     -0.98778240  1.00000000  0.29145844  0.61241400 -0.08949538
## age         -0.27763721  0.29145844  1.00000000 -0.01274609 -0.17164514
## weight      -0.59406188  0.61241400 -0.01274609  1.00000000  0.30827854
## height       0.09788114 -0.08949538 -0.17164514  0.30827854  1.00000000
## neck        -0.47296636  0.49059185  0.11350519  0.83071622  0.25370988
## chest       -0.68259865  0.70262034  0.17644968  0.89419052  0.13489181
## abdomen     -0.79895463  0.81343228  0.23040942  0.88799494  0.08781291
## hip         -0.60933143  0.62520092 -0.05033212  0.94088412  0.17039426
## thigh       -0.55309098  0.55960753 -0.20009576  0.86869354  0.14843561
## knee        -0.49504035  0.50866524  0.01751569  0.85316739  0.28605321
## ankle       -0.26489003  0.26596977 -0.10505810  0.61368542  0.26474369
## biceps      -0.48710872  0.49327113 -0.04116212  0.80041593  0.20781557
## forearm     -0.35164842  0.36138690 -0.08505555  0.63030143  0.22864922
## wrist       -0.32571598  0.34657486  0.21353062  0.72977489  0.32206533
##                   neck      chest     abdomen         hip      thigh
## bodydensity -0.4729664 -0.6825987 -0.79895463 -0.60933143 -0.5530910
## bodyfat      0.4905919  0.7026203  0.81343228  0.62520092  0.5596075
## age          0.1135052  0.1764497  0.23040942 -0.05033212 -0.2000958
## weight       0.8307162  0.8941905  0.88799494  0.94088412  0.8686935
## height       0.2537099  0.1348918  0.08781291  0.17039426  0.1484356
## neck         1.0000000  0.7848350  0.75407737  0.73495788  0.6956973
## chest        0.7848350  1.0000000  0.91582767  0.82941992  0.7298586
## abdomen      0.7540774  0.9158277  1.00000000  0.87406618  0.7666239
## hip          0.7349579  0.8294199  0.87406618  1.00000000  0.8964098
## thigh        0.6956973  0.7298586  0.76662393  0.89640979  1.0000000
## knee         0.6724050  0.7194964  0.73717888  0.82347262  0.7991703
## ankle        0.4778924  0.4829879  0.45322269  0.55838682  0.5397971
## biceps       0.7311459  0.7279075  0.68498272  0.73927252  0.7614774
## forearm      0.6236603  0.5801727  0.50331609  0.54501412  0.5668422
## wrist        0.7448264  0.6601623  0.61983243  0.63008954  0.5586848
##                    knee      ankle      biceps     forearm      wrist
## bodydensity -0.49504035 -0.2648900 -0.48710872 -0.35164842 -0.3257160
## bodyfat      0.50866524  0.2659698  0.49327113  0.36138690  0.3465749
## age          0.01751569 -0.1050581 -0.04116212 -0.08505555  0.2135306
## weight       0.85316739  0.6136854  0.80041593  0.63030143  0.7297749
## height       0.28605321  0.2647437  0.20781557  0.22864922  0.3220653
## neck         0.67240498  0.4778924  0.73114592  0.62366027  0.7448264
## chest        0.71949640  0.4829879  0.72790748  0.58017273  0.6601623
## abdomen      0.73717888  0.4532227  0.68498272  0.50331609  0.6198324
## hip          0.82347262  0.5583868  0.73927252  0.54501412  0.6300895
## thigh        0.79917030  0.5397971  0.76147745  0.56684218  0.5586848
## knee         1.00000000  0.6116082  0.67870883  0.55589819  0.6645073
## ankle        0.61160820  1.0000000  0.48485454  0.41904999  0.5661946
## biceps       0.67870883  0.4848545  1.00000000  0.67825513  0.6321264
## forearm      0.55589819  0.4190500  0.67825513  1.00000000  0.5855883
## wrist        0.66450729  0.5661946  0.63212642  0.58558825  1.0000000

Some variable are correlated, as an example, the variables “Body Density” and “Weight”, this significant correlation is reasonable and expected.

In other hands, some correlations presented high coefficients although not expected. One example is the high correlation coefficient for the variables “Weight” and “Circumference of the neck”

As explained, the objective of this study is to estimate the Body Density of male individuals based only on various body circumferences, for this, a linear regression is recommendaded:

bodymodel <- lm(bodydensity ~ age + weight + height + neck + chest + abdomen + hip + thigh + knee + ankle + biceps + forearm + wrist, data=body)

The linear regression model shows an adjusted R-squared of 0.7238. This is a significant result and indicates that the calculation can be used with confidence. The results are here:

summary(bodymodel)
## 
## Call:
## lm(formula = bodydensity ~ age + weight + height + neck + chest + 
##     abdomen + hip + thigh + knee + ankle + biceps + forearm + 
##     wrist, data = body)
## 
## Residuals:
##       Min        1Q    Median        3Q       Max 
## -0.021527 -0.007717  0.000096  0.006491  0.034114 
## 
## Coefficients:
##               Estimate Std. Error t value Pr(>|t|)    
## (Intercept)  1.139e+00  4.030e-02  28.248  < 2e-16 ***
## age         -1.203e-04  7.515e-05  -1.601  0.11062    
## weight       2.395e-04  1.243e-04   1.926  0.05528 .  
## height       1.498e-04  2.230e-04   0.672  0.50243    
## neck         1.075e-03  5.401e-04   1.991  0.04765 *  
## chest        1.232e-04  2.303e-04   0.535  0.59339    
## abdomen     -2.277e-03  2.008e-04 -11.335  < 2e-16 ***
## hip          5.513e-04  3.390e-04   1.626  0.10521    
## thigh       -6.149e-04  3.354e-04  -1.833  0.06799 .  
## knee        -4.844e-05  5.622e-04  -0.086  0.93141    
## ankle       -6.314e-04  5.145e-04  -1.227  0.22094    
## biceps      -5.755e-04  3.976e-04  -1.448  0.14907    
## forearm     -1.017e-03  4.626e-04  -2.198  0.02891 *  
## wrist        3.959e-03  1.243e-03   3.185  0.00164 ** 
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## 
## Residual standard error: 0.01 on 238 degrees of freedom
## Multiple R-squared:  0.7381, Adjusted R-squared:  0.7238 
## F-statistic:  51.6 on 13 and 238 DF,  p-value: < 2.2e-16

I used my own measures to estimate my Body Fat and for this, I used the predict model below:

predbody <- predict.glm(bodymodel, data.frame(age=39, weight=171 ,height=5.7 ,neck=38 ,chest=104 ,abdomen=96 ,hip=102 , thigh=55 ,knee=39 ,ankle=24 ,biceps=37 ,forearm=27 ,wrist=18),type="response")

This are the results:

summary(predbody)
##    Min. 1st Qu.  Median    Mean 3rd Qu.    Max. 
##   1.039   1.039   1.039   1.039   1.039   1.039

In conclusion, this model allows individuals and professionals to estimate the body fat for men without using expensive techniques and this method is statistically accepted.

However this model is limited as it is based on men and excludes women, there is also other influences, such as: race, daily activities/habits, age range, genetics, etc.

I would to analyse other samples to identify similar patterns regarding this estimation.