Question

1. Find the area under the standard normal distribution for each z score.

a. Between 1.56 and 1.96

b. To the right of 1.75

c. To the left of 1.36

2. The average amount of rain per year in Greenville is 49 inches. The standard deviation is 7.5 inches. Find the probability that next year Greenville will receive the following amount of rainfall. Assume the variable is normally distributed.

a. At most 55 inches of rain

b. At least 62 inches of rain

c. Between 46 and 54 inches of rain

3. The average thickness of books on a library shelf is 8.3 centimeters. The standard deviation is 0.6 centimeters. If 20% of the books are oversized, find the minimum thickness of the oversized books on the library shelf. Assume the variable is normally distributed.

4. The average repair cost of a microwave oven is $85, with a standard deviation of $8. The costs are normally distributed If 400 ovens are repaired, how many would have a repair bill greater than $100?

5. The average number of years a person takes to complete a graduate degree program is 3. The standard deviation is 4 months. Assume the variable is normally distributed. Convert each of the following x intervals to standard z intervals.

a. X> 4

b. X<3

Answer 1