According to an avid aquarist, the average number of fish in a 20-gallon tank is 10, with a standard deviation of two. His friend, also an aquarist, does not believe that the standard deviation is two. She counts the number of fish in 15 other 20-gallon tanks. Based on the results that follow, do you think that the standard deviation is different from two at the 5% level? Data: 11; 10; 10; 10; 10; 11; 11; 10; 12; 9; 8; 11; 11; 10; 11.
A) What is the test statistic? (Round your answer to three decimal places.)
B)What is/are the critical value(s)? (Round your answer(s) to three decimal places
C)What is the decision of the test and what conclusions can be drawn?