Question

Please use RStudio to answer the question and give the R command:

please load data use data:

library(MASS)

data(cats)

Use the “cats” data set to test for the variance of the body weight in male and female cats

Answer 1

Solution:

library(MASS)

data(cats)
dim(cats)
print(cats)

library(dplyr)
var_group= cats %>% group_by(Sex) %>%
summarise_at(vars(Bwt), funs(n(), var(., na.rm = TRUE)))
print(var_group)

Output

Sex n var
<fct> <int> <dbl>
1 F 47 0.0751
2 M 97 0.219
>