Construct a histogram of the PC Knowledge variable. [Because there are only five possible responses (1-5), this histogram should have only five bars.]
Repeat this separately for those who own a PC and those who do not.
Then find a 95% confidence interval for the mean value of PC Knowledge for all of Soft Bus's prospective customers; and of all its prospective customers who own PCs; and of all its prospective customers who do not own PCs.
The PC Knowledge variable obviously can't be exactly normally distributed because it has only five possible values. Do you think this invalidates the confidence intervals? Explain your choice.