#1 A food processor wants to compare two preservatives for their effects on reta

Question

#1 A food processor wants to compare two preservatives for their effects on retarding spoilage. Suppose 16 cuts of fresh meat are treated with preservative A and 16 are treated with preservative B, and the number of hours until spoilage begins is recorded for each of the 32 cuts of meat. The results are summarized in the table below Preservative A Preservative B Sample Mean 108.7 hours 98.7 hours Sample Standard Deviation 10.5 hours 13.6 hours Assume the population variances are equal. What is the 95% confidence interval for (1 - 2)? A (1.2288, 18.7712) B(-1.8124, 21.8124) C (98.7000, 108.7000) D (2.7107, 17.2893)

#2 You work for a manufacturing company and have been asked to compare the output of two of your plants. Specifcially, you are to determine if the daily production amounts of the two plants are statistically different. You draw independent samples from the two plants and obtain the following sample statistics: Plant 1: Average output: 9 Standard deviation: 1 Sample size: 5 Plant 2: Average output: 4 Standard deviation: 1 Sample size: 4 Assume the population variances of the output from the two plants are equal. What is the upper bound of the 95% confidence interval for the differene of the population means? Specifically, find the confidence interval for left parenthesis italic mu subscript 1 minus italic mu subscript 2 right parenthesis

#3 If we are testing for the difference between the means of two independent populations with equal variances, samples of n1 = 15 and n2 = 15 are taken, then the number of degrees of freedom is equal to___

Explanation / Answer

1. The statistical software output for this problem is:

Two sample T summary confidence interval:
1 : Mean of Population 1
2 : Mean of Population 2
1 - 2 : Difference between two means
(with pooled variances)

95% confidence interval results:

Hence,

After mapping the closest option with output, 95% confidence interval will be: (1.2288, 18.77212)

Option A is correct.

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