TABLE 10-14
The use of preservatives by food processors has become a controversial issue. Suppose two preservatives are extensively tested and determined safe for use in meats. A processor wants to compare the preservatives for their effects on retarding spoilage. Suppose 15 cuts of fresh meat are treated with preservative I and 15 are treated with preservative II, and the number of hours until spoilage begins is recorded for each of the 30 cuts of meat. The results are summarized in the table below.
Preservative I Preservative II
I = 106.4 hours II = 96.54 hours
SI = 10.3 hours SII = 13.4 hours
-Referring to Table 10-14, what assumptions are necessary for testing if the population variances differ for preservatives I and II?
A) Both sampled populations are normally distributed.
B) Both samples are random and independent.
C) Neither A nor B is necessary.
D) Both A and B are necessary.

Question

TABLE 10-14
The use of preservatives by food processors has become a controversial issue. Suppose two preservatives are extensively tested and determined safe for use in meats. A processor wants to compare the preservatives for their effects on retarding spoilage. Suppose 15 cuts of fresh meat are treated with preservative I and 15 are treated with preservative II, and the number of hours until spoilage begins is recorded for each of the 30 cuts of meat. The results are summarized in the table below.
Preservative I Preservative II
I  = 106.4 hours  II = 96.54 hours
SI = 10.3 hours SII = 13.4 hours
-Referring to Table 10-14, what assumptions are necessary for testing if the population variances differ for preservatives I and II?
A) Both sampled populations are normally distributed. 
B) Both samples are random and independent. 
C) Neither A nor B is necessary. 
D) Both A and B are necessary.

Quizplus · Accepted Answer

For testing if the population variances differ for preservatives I and II, two assumptions are necessary. 
The first assumption is that both sampled populations are normally distributed, which is necessary to use a variance test.
The second assumption is that both samples are random and independent, which is necessary to ensure that the samples provide accurate representations of the respective populations. Therefore, both A and B are necessary.

TABLE 10-14 the Use of Preservatives by Food Processors Has Become a Become