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The annual sales of romance novels follow the normal distribution. However, the mean and
Chapter 0, Problem 67(choose chapter or problem)
The annual sales of romance novels follow the normal distribution. However, the mean and the standard deviation are unknown. Forty percent of the time sales are more than 470,000, and 10 percent of the time sales are more than 500,000. What are the mean and the standard deviation?
Questions & Answers
QUESTION:
The annual sales of romance novels follow the normal distribution. However, the mean and the standard deviation are unknown. Forty percent of the time sales are more than 470,000, and 10 percent of the time sales are more than 500,000. What are the mean and the standard deviation?
ANSWER:Step 1 of 4
Given:
Let us determine the z-score that corresponds with a probability of in the normal probability table of the appendix. We note that the closest probability is which lies in the row and in the column of the normal probability table and thus the corresponding z-score is then .