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11.11 A nutritionist has noticed a FoodFarm ad stat-ing the company’s peanut but

ID: 3124335 • Letter: 1

Question

11.11 A nutritionist has noticed a FoodFarm ad stat-ing the company’s peanut butter contains less fat than that produced by a major competitor. She purchases 11 8-ounce jars of each brand and measures the fat content of each. The 11 FoodFarm jars had an aver-age of 31.3 grams of fat, with a standard deviation of 2.1 grams. The 11 jars from the other company had an average of 33.2 grams of fat, with a standard deviation of 1.8 grams. Assuming normal populations with equal standard deviations, use the 0.05 level of significance in examining whether FoodFarm’s ad claim could be valid. What is the most accurate statement that could be made about the p -value for this test?

Explanation / Answer

Observed difference (Sample 1 - Sample 2): -1.9
Standard Deviation of Difference : 0.8339

Equal Variances
Pooled Standard Deviation: 1.9558
Pooled DF: 20
95% Confidence Interval for the Difference ( -3.6395 , -0.1605 )
T-Value -2.2783
Population 1 Population 2: P-Value = 0.0338

thus, Null hypothesis can't be rejected since t-calculated is within the critical limits.

Hope this helps.

N Mean StDev SE Mean Sample 1 11 31.3 2.1 0.6332 Sample 2 11 33.2 1.8 0.5427