Setup

setwd = "E:\\Box Sync\\Box Sync\\CUNY\\Summer Bridge 2017\\Week2 - R"

Question 1

Summary to gain overview of the dataset. Display mean and median for two attributes.

summary(quakes)
##       lat              long           depth            mag      
##  Min.   :-38.59   Min.   :165.7   Min.   : 40.0   Min.   :4.00  
##  1st Qu.:-23.47   1st Qu.:179.6   1st Qu.: 99.0   1st Qu.:4.30  
##  Median :-20.30   Median :181.4   Median :247.0   Median :4.60  
##  Mean   :-20.64   Mean   :179.5   Mean   :311.4   Mean   :4.62  
##  3rd Qu.:-17.64   3rd Qu.:183.2   3rd Qu.:543.0   3rd Qu.:4.90  
##  Max.   :-10.72   Max.   :188.1   Max.   :680.0   Max.   :6.40  
##     stations     
##  Min.   : 10.00  
##  1st Qu.: 18.00  
##  Median : 27.00  
##  Mean   : 33.42  
##  3rd Qu.: 42.00  
##  Max.   :132.00
mean(quakes$depth)
## [1] 311.371
mean(quakes$mag)
## [1] 4.6204
median(quakes$depth)
## [1] 247
median(quakes$mag)
## [1] 4.6

Question 2

Create a new data frame with a subset of the columns and rows. Make sure to rename it.

quakes_subset = subset(quakes, depth > mean(quakes$depth), select = c(depth,mag))

Question 3

Create new column names for the new data frame

colnames(quakes_subset) <- c("depth_above_average", "magnitude")

Question 4

Use the summary function to create an overview of your new data frame. The print the mean and median for the same two attributes. Please compare.

Comparions: Mean and median of the depth of the subset is much higher at 535 and 554 compared to 311,247 in the original dataset. More interstinginly, mean and median of magntiude of the subet is both 4.5 compared to both 4.6 in the original dataset. Seems like higher depth doesn’t necessarily result in higher magnitude.

summary(quakes_subset)
##  depth_above_average   magnitude    
##  Min.   :315.0       Min.   :4.000  
##  1st Qu.:498.0       1st Qu.:4.200  
##  Median :554.0       Median :4.500  
##  Mean   :535.6       Mean   :4.525  
##  3rd Qu.:594.0       3rd Qu.:4.700  
##  Max.   :680.0       Max.   :5.900
print(mean(quakes_subset$depth_above_average))
## [1] 535.5833
print(mean(quakes_subset$magnitude))
## [1] 4.525225
print(median(quakes_subset$depth_above_average))
## [1] 554
print(median(quakes_subset$magnitude))
## [1] 4.5

Question 5

For at least 3 values in a column please rename so that every value in that column is renamed. For example, suppose I have 20 values of the letter “e” in one column. Rename those values so that all 20 would show as “excellent”

Changing if magnitudes is greater than 4.9, change to 6

quakes_subset_replace = quakes_subset
quakes_subset_replace[quakes_subset_replace$magnitude > 4.9, "magnitude"] <- 6

Question 6

Display enough rows to see examples of all of steps 1-5 above.

print(quakes[1:67,])
##       lat   long depth mag stations
## 1  -20.42 181.62   562 4.8       41
## 2  -20.62 181.03   650 4.2       15
## 3  -26.00 184.10    42 5.4       43
## 4  -17.97 181.66   626 4.1       19
## 5  -20.42 181.96   649 4.0       11
## 6  -19.68 184.31   195 4.0       12
## 7  -11.70 166.10    82 4.8       43
## 8  -28.11 181.93   194 4.4       15
## 9  -28.74 181.74   211 4.7       35
## 10 -17.47 179.59   622 4.3       19
## 11 -21.44 180.69   583 4.4       13
## 12 -12.26 167.00   249 4.6       16
## 13 -18.54 182.11   554 4.4       19
## 14 -21.00 181.66   600 4.4       10
## 15 -20.70 169.92   139 6.1       94
## 16 -15.94 184.95   306 4.3       11
## 17 -13.64 165.96    50 6.0       83
## 18 -17.83 181.50   590 4.5       21
## 19 -23.50 179.78   570 4.4       13
## 20 -22.63 180.31   598 4.4       18
## 21 -20.84 181.16   576 4.5       17
## 22 -10.98 166.32   211 4.2       12
## 23 -23.30 180.16   512 4.4       18
## 24 -30.20 182.00   125 4.7       22
## 25 -19.66 180.28   431 5.4       57
## 26 -17.94 181.49   537 4.0       15
## 27 -14.72 167.51   155 4.6       18
## 28 -16.46 180.79   498 5.2       79
## 29 -20.97 181.47   582 4.5       25
## 30 -19.84 182.37   328 4.4       17
## 31 -22.58 179.24   553 4.6       21
## 32 -16.32 166.74    50 4.7       30
## 33 -15.55 185.05   292 4.8       42
## 34 -23.55 180.80   349 4.0       10
## 35 -16.30 186.00    48 4.5       10
## 36 -25.82 179.33   600 4.3       13
## 37 -18.73 169.23   206 4.5       17
## 38 -17.64 181.28   574 4.6       17
## 39 -17.66 181.40   585 4.1       17
## 40 -18.82 169.33   230 4.4       11
## 41 -37.37 176.78   263 4.7       34
## 42 -15.31 186.10    96 4.6       32
## 43 -24.97 179.82   511 4.4       23
## 44 -15.49 186.04    94 4.3       26
## 45 -19.23 169.41   246 4.6       27
## 46 -30.10 182.30    56 4.9       34
## 47 -26.40 181.70   329 4.5       24
## 48 -11.77 166.32    70 4.4       18
## 49 -24.12 180.08   493 4.3       21
## 50 -18.97 185.25   129 5.1       73
## 51 -18.75 182.35   554 4.2       13
## 52 -19.26 184.42   223 4.0       15
## 53 -22.75 173.20    46 4.6       26
## 54 -21.37 180.67   593 4.3       13
## 55 -20.10 182.16   489 4.2       16
## 56 -19.85 182.13   562 4.4       31
## 57 -22.70 181.00   445 4.5       17
## 58 -22.06 180.60   584 4.0       11
## 59 -17.80 181.35   535 4.4       23
## 60 -24.20 179.20   530 4.3       12
## 61 -20.69 181.55   582 4.7       35
## 62 -21.16 182.40   260 4.1       12
## 63 -13.82 172.38   613 5.0       61
## 64 -11.49 166.22    84 4.6       32
## 65 -20.68 181.41   593 4.9       40
## 66 -17.10 184.93   286 4.7       25
## 67 -20.14 181.60   587 4.1       13
print(quakes_subset[1:67,])
##     depth_above_average magnitude
## 1                   562       4.8
## 2                   650       4.2
## 4                   626       4.1
## 5                   649       4.0
## 10                  622       4.3
## 11                  583       4.4
## 13                  554       4.4
## 14                  600       4.4
## 18                  590       4.5
## 19                  570       4.4
## 20                  598       4.4
## 21                  576       4.5
## 23                  512       4.4
## 25                  431       5.4
## 26                  537       4.0
## 28                  498       5.2
## 29                  582       4.5
## 30                  328       4.4
## 31                  553       4.6
## 34                  349       4.0
## 36                  600       4.3
## 38                  574       4.6
## 39                  585       4.1
## 43                  511       4.4
## 47                  329       4.5
## 49                  493       4.3
## 51                  554       4.2
## 54                  593       4.3
## 55                  489       4.2
## 56                  562       4.4
## 57                  445       4.5
## 58                  584       4.0
## 59                  535       4.4
## 60                  530       4.3
## 61                  582       4.7
## 63                  613       5.0
## 65                  593       4.9
## 67                  587       4.1
## 68                  627       5.0
## 69                  530       4.5
## 74                  506       5.2
## 75                  546       4.4
## 76                  564       4.3
## 79                  323       4.2
## 82                  367       4.5
## 83                  579       4.6
## 85                  450       4.0
## 88                  538       4.5
## 93                  497       5.2
## 96                  375       4.0
## 97                  365       4.5
## 100                 484       4.7
## 102                 583       4.6
## 103                 608       4.7
## 105                 636       4.6
## 112                 388       4.2
## 113                 477       4.0
## 114                 617       4.8
## 115                 606       4.4
## 116                 609       4.2
## 123                 606       4.7
## 124                 571       4.5
## 125                 328       4.4
## 127                 517       4.2
## 128                 600       5.0
## 132                 527       4.2
## 134                 510       4.6
print(quakes_subset_replace[1:67,])
##     depth_above_average magnitude
## 1                   562       4.8
## 2                   650       4.2
## 4                   626       4.1
## 5                   649       4.0
## 10                  622       4.3
## 11                  583       4.4
## 13                  554       4.4
## 14                  600       4.4
## 18                  590       4.5
## 19                  570       4.4
## 20                  598       4.4
## 21                  576       4.5
## 23                  512       4.4
## 25                  431       6.0
## 26                  537       4.0
## 28                  498       6.0
## 29                  582       4.5
## 30                  328       4.4
## 31                  553       4.6
## 34                  349       4.0
## 36                  600       4.3
## 38                  574       4.6
## 39                  585       4.1
## 43                  511       4.4
## 47                  329       4.5
## 49                  493       4.3
## 51                  554       4.2
## 54                  593       4.3
## 55                  489       4.2
## 56                  562       4.4
## 57                  445       4.5
## 58                  584       4.0
## 59                  535       4.4
## 60                  530       4.3
## 61                  582       4.7
## 63                  613       6.0
## 65                  593       4.9
## 67                  587       4.1
## 68                  627       6.0
## 69                  530       4.5
## 74                  506       6.0
## 75                  546       4.4
## 76                  564       4.3
## 79                  323       4.2
## 82                  367       4.5
## 83                  579       4.6
## 85                  450       4.0
## 88                  538       4.5
## 93                  497       6.0
## 96                  375       4.0
## 97                  365       4.5
## 100                 484       4.7
## 102                 583       4.6
## 103                 608       4.7
## 105                 636       4.6
## 112                 388       4.2
## 113                 477       4.0
## 114                 617       4.8
## 115                 606       4.4
## 116                 609       4.2
## 123                 606       4.7
## 124                 571       4.5
## 125                 328       4.4
## 127                 517       4.2
## 128                 600       6.0
## 132                 527       4.2
## 134                 510       4.6

Question 7

Read in R from github

require(RCurl)
## Loading required package: RCurl
## Loading required package: bitops
quakes_temp <-read.csv(text=getURL("https://raw.githubusercontent.com/milkcake81/CUNYSummer2017/R-Assignments/quakes.csv"))