Volvo wants to estimate the variance of miles per gallon for its auto model XC 90. A random sample of 20 cars of this model showed that the variance of miles per gallon for these cars is 0.62. Test whether the sample result indicates that the population variance is different from 0.50 with the significance level, alpha = 0.05. Assume that the population from which a sample is selected is approximately normally distributed. Calculate the value of the test statistic.

Select one:

a. 23.56

b. 15.32

c. 24.80

d. 43.40