Construct a histogram of the PCKnowledge variable. 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 PCKnowledge for all of SoftBus’s prospective customers; of all its prospective customers who own PCs; of all its prospective customers who do not own PCs. The PCKnowledge 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.