pg. 764 #1-3, 9-11

10. A normal distribution has a mean of 29.3 and a standard deviation of 6.7. What percent of the data will be between 22.6 and 42.7?

79.5%

3. The number of texts sent per day by a sample of 811 teens is normally distributed with a mean of 38 and a standard deviation of 7. a. About how many teens sent between 24 and 38 texts? b. What is the probability that a teen selected at random sent less than 45 texts?

a. about 386 b. 84%

11. The number of visits to a gym per year by a sample of 522 members is normally distributed with a mean of 88 and a standard deviation of 19. a. About how many members went to the gym at least 50 times? b. What is the probability that a member selected at random went to the gym more than 145 times?

a. about 509 b. 0.15%

2. A normal distribution has a mean of 416 and a standard deviation of 55. What percent of the data will be less than 361?

16%

1. A normal distribution has a mean of 416 and a standard deviation of 55. Find the range of values that represent the middle 99.7% of the data.

251 < x < 581

9. A normal distribution has a mean of 29.3 and a standard deviation of 6.7. Find the range of values that represent the outside 5% of the distribution.

x < 15.9 or x > 42.7