Question

8.The heights of 18 year old men are approximately normally distributed, with mean 68 inches and standard deviation 3 inches. If a random sample of nine 18 year old men is selected, what is the probability that the mean height ?̅ is between 67 and 69 inches?

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9. Startup costs (in thousands of dollars) for a random sample of candy stores are given below.

95 173 129 95 75 94 116 100 85

?̅ = 106.9 ??? ? = 29.4

Find a 90% confidence interval for the population average startup costs ? for candy store franchises.

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Answer 1

Question No. 8

Given:

= 68, = 3, n = 9

Find:

..............Using standard Normal table

Question No. 9:

Given: = 106.9, S = 29.4, = 0.1

Degrees of freedom = n-1 = 9-1 = 8

Critical value:

                   ................Using t table

90% Confidence interval:

We are 90% Confident that the population average startup costs for candy store franchises is lies in this interval