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Unformatted text preview: ed. (Recall from section 4.4 that we can assume that the sampling distribution
of x is normal for values of n greater than 30.)
1. Suppose your class is investigating the weights of Snickers 1-ounce fun-size candy bars to see if
customers are getting full value for their money. Assume that the weights are normally distributed with
standard deviation σ =.005 ounces. Several candy bars are randomly selected and weighed with
sensitive balances borrowed from the physics lab.
The weights are:
1.05 1.01 .98
We want to determine a 90% confidence interval for the true mean, µ .
a. What is the sample mean?
b. Determine z * .
c. Determine the 90% confidence interval. (Show your work)
d. Write a sentence that explains the significance of the confidence interval. 2. A SRS of 16 seniors from HISD had a mean SAT-math score of 500 and a standard deviation of 100.
We know that the population of SAT-math scores for seniors in the district is approximately normally
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- Spring '08