A feed supply company has developed a special feed supplemen

A feed supply company has developed a special feed supplement to see if it will promote weight gain in livestock. Their researchers report that the 77 cows studied gained an average of 56 pounds and that a 95% confidence interval for the mean weight gain this supplement produces has a margin of error of +/

Solution

1. The interpretation by the first staff member was that 95% of the cows studied gained between 45 and 67 pounds.

Incorrect. The 95 % confidence interval refers to the population mean of cows, not the cows sampled.

2. The interpretation by the 2nd staff member was that one can be 95% sure that a cow fed this supplement will gain between 45 and 67 pounds.

Incorrect. . Again, the 95 % confidence interval refers to the population mean.

3. The interpretation by the 3rd staff member was that one can be 95% sure that the average weight gain among cows in this study was between 45 and 67 pounds.

Incorrect. We are 100 % sure the average weight gain of the cows in the study is 56. The 95 % confidence interval refers to the population mean.