95% interval = mean ± 1.96 SD
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
I'll let you do the calculations.
an industrial designer wants to determinethe average amount of time it takes an adult to assemble an easy-to- assembletoy .use the following data (inminites)a random sample, to construct a 95% confidence interval for the mean of the population sampled:17 13 18 19 17 21 29 22 16 28 21 15 26 23 24 20 8 17 17 21 32 18 25 22 16 10 20 22 19 14 30 22 12 24 28 11
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