In elementary school (grades 1 to 6), there is a strong association between a child’s height and the child’s reading ability. taller children tend to be able to read at a higher level. however, there is a very significant confounding variable that is influencing both height and reading ability. what is it?

According to a study conducted in 2015, 18% of shoppers said that they prefer to buy generic instead of name-brand products. suppose that in a recent sample of 1500 shoppers, 315 stated that they prefer to buy generic instead of name-brand products. at a 5% significance level, can you conclude that the proportion of all shoppers who currently prefer to buy generic instead of name-brand products is higher than .18? use both the p-value and the critical-value approaches.