HW 9 confidence lvl T table

Question

If n=13, (x-bar)=38, and s=14, construct a confidence interval at a 98% confidence level. Assume the data came from a normally distributed population.Give your answers to one decimal place.

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Answer 1

CI = xbar +/- t-critical * s/sqrt(n)

t-critical is value for n-1 = 12 DOF and tail probability of 0.01 = 2.681.

CI = 38 +/- 2.681 * 14/sqrt(13)