Reference no: EM132836152

Question 1

The time customers spend shopping on Amazon follows the normal distribution wtih a mean of 10 minutes and a standard deviation of 2 minutes.  Calculate the z-score for a customer that spent 15 minutes shopping on Amazon.

Answer: 

Question 2 

The College Board National Office recently reported that in 2011-2012, the 547,038 high school juniors who took the ACT achieved a mean score of 560 with a standard deviation of 130 on the mathematics portion of the test (https://media.collegeboard.com/digitalServices/pdf/research/2013/TotalGroup-2013.pdf). Assume these test scores are normally distributed.

1. What is the probability that a high school junior who takes the test will score at least 600 on the mathematics portion of the test? If required, round your answer to four decimal places.P (x ≥ 600) = 
2. What is the probability that a high school junior who takes the test will score no higher than 420 on the mathematics portion of the test? If required, round your answer to four decimal places.P (x ≤ 420) = 
3. What is the probability that a high school junior who takes the test will score between 420 and 550 on the mathematics portion of the test? If required, round your answer to four decimal places.P (420 ≤ x ≤ 550) = 
4. How high does a student have to score to be in the top 10% of high school juniors on the mathematics portion of the test? If required, round your answer to the nearest whole number.

Question 3

To boost holiday sales, a jewelry store in Bismarck, North Dakota, is advertising the following promotion: "If more than seven inches of cumulative snow fall on December 24, 25, 26, 27, and 28, you get your money back on all purchase made on December 17." To analyze this promotion, the store manager has collected data and determined that snowfall over this 5-day period in December is normally distributed with an average of 5.8 inches and standard deviation of 0.549 inches. What is the probability that the store will have to refund the money to its December 17 customers? If required, round your answer to four decimal places.

Probability =