Suppose we are interested in the mean scores on an exam. A random sample of 36...

Suppose we are interested in the mean scores on an exam. A random sample of 36 scores is taken and gives a sample mean (sample mean score) of 68 (x̄ = 68). In this example, we have the unusual knowledge that the population standard deviation is 3 points. Do not count on knowing the population parameters outside of textbook examples.

Find a 90% confidence interval for the true (population) mean of statistics exam scores.

Solutions

Expert Solution

Solution :

Given that,

Z_/2 = 1.645

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

= 1.645 * (3 / $\sqrt$ 36)

= 0.82

At 90% confidence interval estimate of the population mean is,

- E < < + E

68 - 0.82 < < 68 + 0.82

67.18 < < 68.82

(67.18 , 68.82)

orchestra answered 1 year ago

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