Question

Noise levels at 6 airports were measured in decibels yielding the following data:

157,164,160,147,152,153

Construct the 99% confidence interval for the mean noise level at such locations. Assume the population is approximately normal.

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Step 4 of 4 :  

Construct the 99% confidence interval. Round your answer to one decimal place.

Answer 1

From the given data

= 155.5 , S = 6.091

t critical value at 0.01 level with 5 df = 4.032

99% confidence interval for is

- t * S / sqrt(n) < < + t * S / sqrt(n)

155.5 - 4.032 * 6.091 / sqrt(6) < < 155.5 + 4.032 * 6.091 / sqrt(6)

145.5 < < 165.5

99% CI is ( 145.5 , 165.5)