Help with B-1

Exercise 11-13 Algo The manager of a supermarket would like the variance of the waiting times of the customers not to exceed 2.8 minutes-squared. She would add a new cash register if the variance exceeds this threshold. She regularly checks the waiting times of the customers to ensure that the variance does not rise above the allowed level. In a recent random sample of 46 customer waiting times, she computes the sample variance as 4.2 minutes-squared. She believes that the waiting times are normally distributed. (You may find it useful to reference the appropriate table: chi-square table or F table) a. Select the null and the alternative hypotheses to test if the threshold has been crossed. " Ha: 02 s 2. 8; HA: 02 > 2.8 Ha: 02 = 2.8; HA: 02 # 2.8 OHp: 02 2 2.8; HA: 02