Stat 160 Postquiz6, Over 5.4-6.2



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1. Suppose the population standard deviation of a normal distribution is 2.0. What is the interquartile range of the distribution?
0.67

1.34
2.68
The mean is 2.
2. The heights of 11-year-old girls are believed to follow a normal distribution with a mean of 58 inches and a standard deviation of 3 inches. What is the probability that an 11-year-old girl is taller than 60 inches?
1.589

.252
.748
1
3. Refer to the situation in problem # 2. How tall is an 11-year-old girl if 75% of 11-year-old girls are shorter than she is?
55.978

59.167
60.022
56.832
4. Refer to the situation in problem # 2. Suppose we now take a sample of 9 11-year-old girls. What is the probability that the average height of the 9 girls exceeds 60 inches? Use CLT.
.252

.748
.023
.997
5. Suppose 9 adult males enter the elevator on the 50th floor of Rood Hall. The posted sign says Max. Wt. 1700 pounds. Determine the probability that they plunge to their death (i.e., that they exceed the maximum weight). Use: the mean and standard deviation of the weight of an adult male are 175 pounds and 15 pounds, respectively.
0.0001

0.9999
0.9973
0.0027