Question

number 15 how do i find the sample size? it is said the p-value is 0.275

13.13 CHAPTER 13 EXERCISES 367 the Grape flavor was right on target for the last test with a variance of 2.30 grams based on a sample of size 16. The machine filling the Fruity flavor had a variance of 2.58 grams for a sample size of 16. Assuming the distribution of the fills for each machine is approximately normal, is there evidence to show that the variability for the machine filling the Fruity flavor is higher than the machine filling the Grape flavor? 15 The Centers for Disease Control and Prevention (CDC) study potential human health risks for people exposed to radioactive releases into the environment. Tritium has been a major concern at several sites. Research has been done to look at not only the mean amount of tritium released but the variability of releases over the years. The annual release amount is known to have an approximately normal distribution. For the years from 1970 to 1979, the standard deviation of the annual release amount was 1500. curies. The standard deviation for the annual measures for the years 1980 through 1989 was 189261 curies. Is there evidence that the variation in the annual releases for the 1970's is less than that of the 1980's? 16. It is believed that spending money on a professional preparation service for the SAT exams will increase your score. Ten students were chosen randomly, five that had taken a preparation class and five that had not. Does this provide evidence that the preparation courses increase the SAT score? Preparation Class 1130 1470 1230 630 1030 No Preparation Class 1010 1240 1270 1020 1350

Answer 1

Here, $n_1$ = number of years between 1970 and 1979 = 10 and $n_2$ = number of years between 1980 and 1989 = 10.



We conclude that there is not enough evidence to suggest that the variation in the annual releases for the 1970's is less than that of the 1980's.

62 = 18926.1. th: (15) Given, bis 15409.9, To test, Ho: +27 02² Now, test statistie - For 0,220² 0.663 An s' 2 to F Faa ni-1, 2-1 0,275 P ( Fara = 0.663) Now, P- value = fail to reject Ho, L2= 0,05, cue Since p- value