# statistics

The following random sample was collected: 22 33 44 6. The 80% confidence interval for the mean is?
I have the answers; however, I do not know how to plug in the numbers to solve the problem.

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1. The sample is too small for a confidence interval to be really meaningful.

Find the mean first = sum of scores/number of scores

Subtract each of the scores from the mean and square each difference. Find the sum of these squares. Divide that by the number of scores to get variance.

Standard deviation = square root of variance

Z = (score-mean)/SEm

SEm = SD/√n

Find table in the back of your statistics text labeled something like "areas under normal distribution" to find the proportion/probability (.40) and its Z score.

Plug that ±Z score into the equation above.

I'll let you do the calculations.

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posted by PsyDAG

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