Exercise 37: Comparison of 2 groups

Which package can you use to get the data in long format? Answer must be one word.

We will do the comparison with lm(). What is the correct code to fit a linear model with lm()?

What is the name of the package that can check normality of the residuals using the output of lm()? Answer should be one word.

Are the residuals normally distributed according to the Shapiro-Wilk and the Anderson-Darling test? 

Can I check the results of lm() now to see if the two groups are different?

Which function can we use to check if the groups have equal spreads? There are two correct answers.

Do the two groups have equal spreads according to the F-test, the test performed by var.test()?

Are the two groups different?

When you do
> summary(fit)

and you look at the output in the console which coefficient shows the difference between the means of the two groups?

Do you want to see the full solution of the comparison of the two groups?

What is the ggplot() command for creating a vertical bar cart of this comparison?

How can we add bars to the plot?

How to add error bars that clearly show that there is a difference between the two groups?

Which function will add the points to the plot? Answer must be one word.

Which function to add a title to the plot? Answer must be one word.

Which function can you use to center the title? Answer must be one word.