The Economic Policy Institute reports that the average entry-level wage for male college graduates is $22.82 per hour and for female college graduates is $18.01 per hour. The standard deviation for male graduates is $3.72 and for female graduates is $3.06. Assume wages are normally distributed. (See exercise 23 on page 326 of your textbook for a similar problem.)
Question 1: If 27 female graduates are chosen, find the probability the sample average entry-level wage is at least $18.89.
30% of consumers read the ingredients listed on a product's label. (See exercise 36 on page 332 of your textbook for a similar problem.)
Question 2: For a sample of 220 consumers, what is the probability that between 57 and 77 of them read the ingredients listed on a product's label?
The number of hours adults sleep per night is normally distributed with a mean of 5.7 hours. Assume that the standard deviation is unknown. (See exercise 39 on page 141 of your textbook for a similar problem.)
Question 3: If 70% of adults sleep more than 5.5 hours per night, what is the variance? (Remember the label.)
Starbucks has found that 28% of customers purchase more than one cup of coffee per day from their shops. Suppose you randomly choose 185 of today's Starbucks customers.
Question 4: Find the probability that no less than 37% of them purchased more than one cup of coffee from Starbucks.
On the SAT, the average Writing score is 480 points and the average Mathematics score is 540 points. The standard deviation is 80 points on each part of the test. Now suppose 44 test takers are selected. (See exercise 21 on page 326 of your textbook for a similar problem.)
Question 5: 97% of the time the sample average Writing score should be less than what? (Remember the label.)
The time it takes to bake a Betty Crocker Supermoist Fudge Cake is normally distributed with a mean of 39 minutes and a variance of 38 minutes^2. Let baking time, in minutes, be represented by random variable X.
Question 6: P(x1 X 44) = 0.0880. Find x1. (Remember the label.)