What is c-2.5 because I don't know it can any one help me

In a graph with several intervals o data how does a constant interval appear? what type of scenario produces a constant interval?

Find cot x if sin x cot x csc x = √2

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.