Chapter 6: Q15 (page 241)
Standard Normal Distribution. Find the indicated z score. The graph depicts the standard normal distribution of bone density scores with mean 0 and standard deviation 1.
Short Answer
The z-score indicated in graph is -1.45.
Chapter 6: Q15 (page 241)
Standard Normal Distribution. Find the indicated z score. The graph depicts the standard normal distribution of bone density scores with mean 0 and standard deviation 1.
The z-score indicated in graph is -1.45.
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Standard Normal DistributionIn Exercises 17–36, assume that a randomly selected subject is given a bone density test. Those test scores are normally distributed with a mean of 0 and a standard deviation of 1. In each case, draw a graph, then find the probability of the given bone density test scores. If using technology instead of Table A-2, round answers
to four decimal places.
Between 2.00 and 3.00.
In Exercises 5–8, find the area of the shaded region. The graphs depict IQ scores of adults, and those scores are normally distributed with a mean of 100 and a standard deviation of 15 (as on the Wechsler IQ test).
In Exercises 9–12, find the area of the shaded region. The graph depicts the standard normal distribution of bone density scores with mean 0 and standard deviation 1.
Quarters After 1964, quarters were manufactured so that their weights have a mean of5.67 g and a standard deviation of 0.06 g. Some vending machines are designed so that you canadjust the weights of quarters that are accepted. If many counterfeit coins are found, you cannarrow the range of acceptable weights with the effect that most counterfeit coins are rejectedalong with some legitimate quarters.
a. If you adjust your vending machines to accept weights between 5.60 g and 5.74 g, what percentage of legal quarters are rejected? Is that percentage too high?
b. If you adjust vending machines to accept all legal quarters except those with weights in the top 2.5% and the bottom 2.5%, what are the limits of the weights that are accepted?
In Exercises 13–20, use the data in the table below for sitting adult males and females (based on anthropometric survey data from Gordon, Churchill, et al.). These data are used often in the design of different seats, including aircraft seats, train seats, theatre seats, and classroom seats. (Hint: Draw a graph in each case.)
Mean | St.Dev. | Distribution | |
Males | 23.5 in | 1.1 in | Normal |
Females | 22.7 in | 1.0 in | Normal |
Find the probability that a male has a back-to-knee length between 22.0 in. and 24.0 in.
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