Question

In: Statistics and Probability

Suppose the mean height in inches of all 9th grade students at one high school is...

Suppose the mean height in inches of all 9th grade students at one high school is estimated. The population standard deviation is 3 inches. The heights of 9 randomly selected students are 60, 61, 70, 65, 65, 60, 69, and 70.

x-bar =

Margin of error at 99% confidence level =

99% confidence interval =

Solutions

Expert Solution

Solution :

Given set of score are

60, 61, 70, 65, 65, 60, 69, and 70.

Mean = x / n

= 60+61+70+65+65+60+69+70 / 8

= 520 / 8 = 65

Mean = 65

Point estimate = sample mean = = 65

population standard deviation = = 3

sample size = n = 9

Z_/2 = 2.576

Margin of error = E = Z_/2* ( / $\sqrt$ n)

= 2.576 * (3 / $\sqrt$ 9)

Margin of error = E = 2.6

At 99% confidence interval estimate of the population mean is,

- E < < + E

65 - 2.6 < < 65 + 2.6

62.4 < < 67.6

99% confidence interval = 62.4 , 67.6

orchestra answered 1 year ago

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