Test of a single variance Use the following information to a

Test of a single variance

Use the following information to answer the next twelve exercises: Suppose an airline claims that it’s flights are consistently on time with an average delay of at most 15 minutes. It claims that the average delay is so consistent that the variance is no more than 150 minutes. Doubting the consistency part of the claim, a disgruntled traveler calculates the delays for his next 25 flights. The average delay for those 25 flights is 22 minutes with a standard deviation of 15 minutes.

What is the df?  

Solution

dF = n-1

= 25 -1

= 24 Answer