For exercises 14 and 15, a set of data has a normal distribution with a mean of 120 and a standard deviation of 10.

14. Find the interval about the mean within which 90% of the data lie. (1 point)
94.2–145.8
103.5–136.5
113.68–126.32
100.4–139.6

15. Find the probability that a value selected at random from this data is between 100 and 140. (1 point)
99.9%
90%
99%
95.5%

In a random sample of 1,000 exams, the average score was 500 points with a standard deviation of 80 points.

16. Find the interval about the sample mean that has a 1% level of confidence. (1 point)
499–501
479–520
495–505
493–507

17. Find the interval about the sample mean such that the probability is 0.90 that the mean number lies within the interval.
(1 point)
499–501
495–505
496–504
368–632

18. Find the probability that the mean score of the population will be less than five points from the mean score of the sample.
(1 point)
95.5%
38.3%
98.8%
62.5%

19. Find the probability that the true mean is between 495 and 500.
(1 point)
95%
47.75%
95.5%
68.3%

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