# help(swiss)
summary(swiss)
##    Fertility      Agriculture     Examination      Education    
##  Min.   :35.00   Min.   : 1.20   Min.   : 3.00   Min.   : 1.00  
##  1st Qu.:64.70   1st Qu.:35.90   1st Qu.:12.00   1st Qu.: 6.00  
##  Median :70.40   Median :54.10   Median :16.00   Median : 8.00  
##  Mean   :70.14   Mean   :50.66   Mean   :16.49   Mean   :10.98  
##  3rd Qu.:78.45   3rd Qu.:67.65   3rd Qu.:22.00   3rd Qu.:12.00  
##  Max.   :92.50   Max.   :89.70   Max.   :37.00   Max.   :53.00  
##     Catholic       Infant.Mortality
##  Min.   :  2.150   Min.   :10.80   
##  1st Qu.:  5.195   1st Qu.:18.15   
##  Median : 15.140   Median :20.00   
##  Mean   : 41.144   Mean   :19.94   
##  3rd Qu.: 93.125   3rd Qu.:21.70   
##  Max.   :100.000   Max.   :26.60
head(swiss)
##              Fertility Agriculture Examination Education Catholic
## Courtelary        80.2        17.0          15        12     9.96
## Delemont          83.1        45.1           6         9    84.84
## Franches-Mnt      92.5        39.7           5         5    93.40
## Moutier           85.8        36.5          12         7    33.77
## Neuveville        76.9        43.5          17        15     5.16
## Porrentruy        76.1        35.3           9         7    90.57
##              Infant.Mortality
## Courtelary               22.2
## Delemont                 22.2
## Franches-Mnt             20.2
## Moutier                  20.3
## Neuveville               20.6
## Porrentruy               26.6
# number of rows of dataset
nrow(swiss)
## [1] 47

Histogram plot

hist(swiss$Agriculture, breaks = 5, col = "darkgreen",
     xlab = "Percent of males involved in agriculture in an occupation",
     main = "Agriculture Distribution")

Explanation: The histogram displays how 47 Swiss provinces are distributed across the proportion of males enforcement employed in agriculture. The X-axis divides these percentage into intervals of 20%, and the y-axis represents how many provinces fall into that percent. The graph is left-skewed. There are 16 provinces that fall into the 60-80% range, while there are 11 provinces fall into the 40 - 60% range

Scatter plot

plot(swiss$Catholic, swiss$Fertility, col="orange",
     xlab = "Catholic Percentage",
     ylab = "Fertility",
     main = "Scatter plot")

Explanation: Each point represents one Swiss province. The plot helps visualize how fertility changes with Catholic percentage. There are 2 obvious clusters: Provinces with very low and high Catholic percentage tend to have higher fertility, while provinces with moderate Catholic percentage tend to have lower fertility.

2 subsets

#set Threshold
threshold <- median(swiss$Education)
threshold
## [1] 8
#subset lowEdu
lowEdu <- subset(swiss, Education < threshold)
nrow(lowEdu)
## [1] 21
lowEdu
##              Fertility Agriculture Examination Education Catholic
## Franches-Mnt      92.5        39.7           5         5    93.40
## Moutier           85.8        36.5          12         7    33.77
## Porrentruy        76.1        35.3           9         7    90.57
## Broye             83.8        70.2          16         7    92.85
## Gruyere           82.4        53.3          12         7    97.67
## Veveyse           87.1        64.5          14         6    98.61
## Aubonne           66.9        67.5          14         7     2.27
## Cossonay          61.7        69.3          22         5     2.82
## Echallens         68.3        72.6          18         2    24.20
## Moudon            65.0        55.1          14         3     4.52
## Orbe              57.4        54.1          20         6     4.20
## Oron              72.5        71.2          12         1     2.40
## Paysd'enhaut      72.0        63.5           6         3     2.56
## Conthey           75.5        85.9           3         2    99.71
## Entremont         69.3        84.9           7         6    99.68
## Herens            77.3        89.7           5         2   100.00
## Martigwy          70.5        78.2          12         6    98.96
## Monthey           79.4        64.9           7         3    98.22
## Sierre            92.2        84.6           3         3    99.46
## Val de Ruz        77.6        37.6          15         7     4.97
## ValdeTravers      67.6        18.7          25         7     8.65
##              Infant.Mortality
## Franches-Mnt             20.2
## Moutier                  20.3
## Porrentruy               26.6
## Broye                    23.6
## Gruyere                  21.0
## Veveyse                  24.5
## Aubonne                  19.1
## Cossonay                 18.7
## Echallens                21.2
## Moudon                   22.4
## Orbe                     15.3
## Oron                     21.0
## Paysd'enhaut             18.0
## Conthey                  15.1
## Entremont                19.8
## Herens                   18.3
## Martigwy                 19.4
## Monthey                  20.2
## Sierre                   16.3
## Val de Ruz               20.0
## ValdeTravers             19.5
#subset HighEdu
highEdu <- subset(swiss, Education >= threshold)
nrow(highEdu)
## [1] 26
highEdu
##              Fertility Agriculture Examination Education Catholic
## Courtelary        80.2        17.0          15        12     9.96
## Delemont          83.1        45.1           6         9    84.84
## Neuveville        76.9        43.5          17        15     5.16
## Glane             92.4        67.8          14         8    97.16
## Sarine            82.9        45.2          16        13    91.38
## Aigle             64.1        62.0          21        12     8.52
## Avenches          68.9        60.7          19        12     4.43
## Grandson          71.7        34.0          17         8     3.30
## Lausanne          55.7        19.4          26        28    12.11
## La Vallee         54.3        15.2          31        20     2.15
## Lavaux            65.1        73.0          19         9     2.84
## Morges            65.5        59.8          22        10     5.23
## Nyone             56.6        50.9          22        12    15.14
## Payerne           74.2        58.1          14         8     5.23
## Rolle             60.5        60.8          16        10     7.72
## Vevey             58.3        26.8          25        19    18.46
## Yverdon           65.4        49.5          15         8     6.10
## St Maurice        65.0        75.9           9         9    99.06
## Sion              79.3        63.1          13        13    96.83
## Boudry            70.4        38.4          26        12     5.62
## La Chauxdfnd      65.7         7.7          29        11    13.79
## Le Locle          72.7        16.7          22        13    11.22
## Neuchatel         64.4        17.6          35        32    16.92
## V. De Geneve      35.0         1.2          37        53    42.34
## Rive Droite       44.7        46.6          16        29    50.43
## Rive Gauche       42.8        27.7          22        29    58.33
##              Infant.Mortality
## Courtelary               22.2
## Delemont                 22.2
## Neuveville               20.6
## Glane                    24.9
## Sarine                   24.4
## Aigle                    16.5
## Avenches                 22.7
## Grandson                 20.0
## Lausanne                 20.2
## La Vallee                10.8
## Lavaux                   20.0
## Morges                   18.0
## Nyone                    16.7
## Payerne                  23.8
## Rolle                    16.3
## Vevey                    20.9
## Yverdon                  22.5
## St Maurice               17.8
## Sion                     18.1
## Boudry                   20.3
## La Chauxdfnd             20.5
## Le Locle                 18.9
## Neuchatel                23.0
## V. De Geneve             18.0
## Rive Droite              18.2
## Rive Gauche              19.3

explanation: I created a threshold using the median value of the Education column of dataset. Then I split the dataset into 2 groups: lowEdu, which contains all rows where Education is below the threshold, and highEdu, which contains all rows where Educaiton is greater than or equal to the threshold. This allows me to compare provinces with lower versus higher educaiton levels.

T-test

t.test(lowEdu$Agriculture, highEdu$Agriculture)
## 
##  Welch Two Sample t-test
## 
## data:  lowEdu$Agriculture and highEdu$Agriculture
## t = 3.3672, df = 44.395, p-value = 0.001577
## alternative hypothesis: true difference in means is not equal to 0
## 95 percent confidence interval:
##   8.07062 32.12022
## sample estimates:
## mean of x mean of y 
##  61.77619  41.68077

explanation: Based on the T-test results, the mean Agriculture value in the low-Education group is significantly different from the mean Agriculture value in the high-Education group. The p-value ia 0.0016, which is below the 0.05 significance level. Therefore, I can conclude that the difference between two means is statistically significant.