According to the Sacramento Bee (2 April 1998, p. F5), Americans get an average of 6 hours and 57 minutes of sleep per night. A sur­vey of a class of 190 statistics students at a large university found that they averaged 7.1 hours of sleep the previous night, with a standard devia­tion of 1.95 hours.
a. Assume that the population average for adults is 6 hours and 57 minutes, or 6.95 hours of sleep per night, with a standard deviation of 2 hours. Draw a picture similar to Figure 19.5, illustrating how the Rule for Sample Means would apply to sample means for random samples of 190 adults.

b. Would the mean of 7.1 hours of sleep obtained from the statistics students be a reasonable value to expect for the sample mean of a random sample of 190 adults? Explain.
c. Can the sample taken in the statistics class be considered to be a representative sample of all adults? Explain.

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95% 6 10 Possible sample means