Question

If n=13, (x-bar)=34, and s=4, construct a confidence interval at a 90% confidence level. Assume the data came from a normally distributed population.

Give your answers to one decimal place.

____ < μμ < ____

Answer 1

Data given:

As we know, the formula for calculating the confidence interval is given as -

where z - value from the z-table for required confidence interval

- mean

- standard deviation

n - sample size

Using the above formula, we can construct a confidence interval at a 90% confidence level as -

(rounded to one decimal place)

Thus, the confidence interval at a 90% confidence level is (32.2, 35.8) .