Suppose it is desired to estimate the average time a customer spends in a particular store to within 5 minutes (e.g., + 5 minutes) at 99 reliability. It is estimated that the standard deviation of the times is 15 minutes.
How large a sample should be taken to get the desired interval?
A) n = 35 B) n = 299 C) n = 25 D) n = 60
Question 2
Suppose a company makes 4 different frozen dinners, and tests their ability to attract customers. They test the frozen dinners in 13 different stores in order to account for any extraneous sources of variation.
The company records the number of customers who purchase each product at each store. What assumptions are necessary for the validity of the F statistic for comparing the response means of the 4 frozen dinners?
A) The means of the observations corresponding to all the block-treatment combinations are equal, and the variances of all the probability distributions are equal.
B) The probability distributions of observations corresponding to all the block-treatment combinations are normal, and the sampling distributions of the variances of all the block-treatment combinations are normally distributed.
C) The probability distributions of observations corresponding to all the block-treatment combinations are normal, and the variances of all the probability distributions are equal.
D) None. The Central Limit Theorem eliminates the need for any assumptions.
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