Construct a 95% confidence interval for the population mean, μ. Assume the population has a normal distribution. A sample of 25 randomly selected students has a mean test score of 81.5 with a standard deviation of 10.2.

The 95% confidence interval for the population mean is between 77.5 and 85.5

Step-by-step explanation:

We have that to find our level, that is the subtraction of 1 by the confidence interval divided by 2. So:

Now, we have to find z in the Ztable as such z has a pvalue of .

So it is z with a pvalue of , so

Now, find M as such

In which is the standard deviation of the population and n is the size of the sample.

The lower end of the interval is the sample mean subtracted by M. So it is 81.5 - 4 = 77.5.

The upper end of the interval is the sample mean added to M. So it is 81.5 + 4 = 85.5

The 95% confidence interval for the population mean is between 77.5 and 85.5

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step-by-step explanation:

898.1666667

step-by-step explanation:

5389/6 = 898.1666667