A company that makes hair-care products had 3,000 people try a new shampoo of the 3,000 21 had a mild allergic reaction. What percent of people had a mild allergic reaction

Pls if a cow has a mass of 9×10^2 kilograms, and a blue whale has a mass of 1.8×10^5 kilograms, which of these statements is true?

Carl's candies has determined that a candy bar measuring 3 inches long has a z-score of +1 and a candy bar measuring 3.75 inches long has a z-score of +2. what is the standard deviation of the length of candy bars produced at carl's candies?

Having a hard time understanding this question (see attachment).