national food product company believes that it sells more frozen pizza during th
ID: 3250605 • Letter: N
Question
national food product company believes that it sells more frozen pizza during the winter months than during the summer months. Average weekly sales for a sample of stores in a metropolitan area over a three-year period provided the following data for sales volume (in pounds) during the two seasons. Complete parts a through c Season Mean StDev Minimum Maximum 30,932 14,017 Winter 16,188 70,745 22,699 8121 56,952 Summer 41 12.450 a) How much difference is there between the mean amount of this brand of frozen pizza sold (in pounds) between the two seasons? (Assume that this time frame represents typical sales in the given metropolitan area.) The positive difference is 8233 b) Construct and interpret a 90% confidence interval for the differences between weekly sales during the winter and summer months. The 90% confidence interval for the difference summer is (Round to two decimal places as needed.)Explanation / Answer
1)
b)
z value at 90% CI = 1.645
CI = (x1 - x2) +/- z * sqrt(s1^2 / n1 + s2^2/n2)
= ( 30932 - 22699) + /- 1.645 * sqrt(14017^2/44 + 8121^2/41)
= (4178.84 , 12287.15)
2)
b)
z value at 90% CI = 1.645
CI = (x1 - x2) +/- z * sqrt(s1^2 / n1 + s2^2/n2)
= (9.167 - 8.764) + /- 1.645 * sqrt(2.458^2/69 + 3.901^2/79)
= (-0.4677, 1.2737)
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