Manufacturing planning wants to estimate plant capacity in order to schedule customer orders and improve on-time delivery. A random sample of ten days output gave the following results for numbers of finished components produced: 577, 642, 615, 655, 600, 570, 640, 620, 595, and 575. Planning is concerned about the variability of daily output and views as undesirable any variance above 525.
a. Calculate the sample variance.
b. Test at the 10% significance level the null hypothesis that the population variance for daily output does not exceed 525.