The graph of which function will have a maximum and a y-intercept of 4? f(x) = 4x2 + 6x – 1
f(x) = –4x2 + 8x + 5
f(x) = –x2 + 2x + 4
f(x) = x2 + 4x – 4

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.