Question

3. [10 pts] A meteorologist who sampled 13 thunderstorms found that the average speed at which they traveled across a certain state was 15 miles per hour. The standard deviation of the sample was 1.7 miles per hour. Find the 99% confidence interval of the mean. Critical T value= Margin of error (E)= J-io for a

Answer 1

solution:-

given that mean = 15 ,standard deviation = 1.7

sample n = 13

degrees of freedom df = n - 1 = 13 - 1 = 12

critical T value = 3.055

Margin of error(E) = T * standard deviation/sqrt(n)

= 3.055*1.7/sqrt(13)

= 1.4404

confidence interval formula

mean +/- margin of error

15 +/- 1.4404

=> 13.5596 < µ < 16.4404