The data in Nutrition- Study, introduced in Exercise 1.13 on page 13, include information on nutrition and health habits of a sample of 315 people. One of the variables is Smoke, indicating whether a person smokes or not (yes or no). Use technology to test whether the data provide evidence that the proportion of smokers is different from 20%.

Exercise 1.13 on page 13

The data from a study examining the association between diet and plasma retinol and beta-carotene levels are given in NutritionStudy. The data include 315 observations and 16 variables that are described in Appendix B on page 691.