R language

Explain the structure of the dataset. Find the mean and median for each of the variables. Describe the problem you found and explain your solution.
Find the mode for x4. Explain how you get the value.
Find the variance for each variable and present your result in a table.
Run an appropriate test to compare variance between x1 and x2. What is the name
of the test you used?
Explain the result of the test you run in 5.