data loading

data <- mtcars

data check

dim(data)
## [1] 32 11
dim(data)[1]
## [1] 32
dim(data)[2]
## [1] 11

basic summary

summary(data)
##       mpg             cyl             disp             hp       
##  Min.   :10.40   Min.   :4.000   Min.   : 71.1   Min.   : 52.0  
##  1st Qu.:15.43   1st Qu.:4.000   1st Qu.:120.8   1st Qu.: 96.5  
##  Median :19.20   Median :6.000   Median :196.3   Median :123.0  
##  Mean   :20.09   Mean   :6.188   Mean   :230.7   Mean   :146.7  
##  3rd Qu.:22.80   3rd Qu.:8.000   3rd Qu.:326.0   3rd Qu.:180.0  
##  Max.   :33.90   Max.   :8.000   Max.   :472.0   Max.   :335.0  
##       drat             wt             qsec             vs        
##  Min.   :2.760   Min.   :1.513   Min.   :14.50   Min.   :0.0000  
##  1st Qu.:3.080   1st Qu.:2.581   1st Qu.:16.89   1st Qu.:0.0000  
##  Median :3.695   Median :3.325   Median :17.71   Median :0.0000  
##  Mean   :3.597   Mean   :3.217   Mean   :17.85   Mean   :0.4375  
##  3rd Qu.:3.920   3rd Qu.:3.610   3rd Qu.:18.90   3rd Qu.:1.0000  
##  Max.   :4.930   Max.   :5.424   Max.   :22.90   Max.   :1.0000  
##        am              gear            carb      
##  Min.   :0.0000   Min.   :3.000   Min.   :1.000  
##  1st Qu.:0.0000   1st Qu.:3.000   1st Qu.:2.000  
##  Median :0.0000   Median :4.000   Median :2.000  
##  Mean   :0.4062   Mean   :3.688   Mean   :2.812  
##  3rd Qu.:1.0000   3rd Qu.:4.000   3rd Qu.:4.000  
##  Max.   :1.0000   Max.   :5.000   Max.   :8.000

detail summary

library(psych)
## Warning: package 'psych' was built under R version 4.3.3
knitr::kable(describe(data))
vars n mean sd median trimmed mad min max range skew kurtosis se
mpg 1 32 20.090625 6.0269481 19.200 19.6961538 5.4114900 10.400 33.900 23.500 0.6106550 -0.3727660 1.0654240
cyl 2 32 6.187500 1.7859216 6.000 6.2307692 2.9652000 4.000 8.000 4.000 -0.1746119 -1.7621198 0.3157093
disp 3 32 230.721875 123.9386938 196.300 222.5230769 140.4763500 71.100 472.000 400.900 0.3816570 -1.2072119 21.9094727
hp 4 32 146.687500 68.5628685 123.000 141.1923077 77.0952000 52.000 335.000 283.000 0.7260237 -0.1355511 12.1203173
drat 5 32 3.596563 0.5346787 3.695 3.5792308 0.7042350 2.760 4.930 2.170 0.2659039 -0.7147006 0.0945187
wt 6 32 3.217250 0.9784574 3.325 3.1526923 0.7672455 1.513 5.424 3.911 0.4231465 -0.0227108 0.1729685
qsec 7 32 17.848750 1.7869432 17.710 17.8276923 1.4158830 14.500 22.900 8.400 0.3690453 0.3351142 0.3158899
vs 8 32 0.437500 0.5040161 0.000 0.4230769 0.0000000 0.000 1.000 1.000 0.2402577 -2.0019376 0.0890983
am 9 32 0.406250 0.4989909 0.000 0.3846154 0.0000000 0.000 1.000 1.000 0.3640159 -1.9247414 0.0882100
gear 10 32 3.687500 0.7378041 4.000 3.6153846 1.4826000 3.000 5.000 2.000 0.5288545 -1.0697507 0.1304266
carb 11 32 2.812500 1.6152000 2.000 2.6538462 1.4826000 1.000 8.000 7.000 1.0508738 1.2570431 0.2855297

visualization

boxplot(data$mpg)

boxplot(data$wt)

boxplot(data$mpg, data$wt)

hist(data$mpg)

hist(data$wt)

plot(data$wt, data$mpg)

Modeling

corr.test(data$wt, data$mpg)
## Call:corr.test(x = data$wt, y = data$mpg)
## Correlation matrix 
## [1] -0.87
## Sample Size 
## [1] 32
## These are the unadjusted probability values.
##   The probability values  adjusted for multiple tests are in the p.adj object. 
## [1] 0
## 
##  To see confidence intervals of the correlations, print with the short=FALSE option