Question

1. Canadians are becoming more conscious of the importance of good nutrition, and some researchers believe that we may be altering our diets to include less red meat and more fruits and vegetables. To test this theory, a researcher decides to select hospital nutritional records for subjects surveyed 10 years ago and to compare the average amount of beef consumed per year to the amounts consumed by an equal number of subjects she will interview this year. She knows that the amount of beef consumed annually by Canadians ranges from 0 to approximately 50 kg. How many subjects should the researcher select for each group if she wishes to estimate the difference in the average annual per-capita beef consumption correct to within 2.7 kg with 99% confidence? (Round your answer up to the nearest whole number.)
__ subjects

2. A random sampling of a company's monthly operating expenses for n = 81 months produced a sample mean of $5,537 and a standard deviation of $768. Find a 90% upper confidence bound for the company's mean monthly expenses. (Round your answer to two decimal places.)
$___

3. Independent random samples of n₁ = n₂ = n observations are to be selected from each of two populations 1 and 2. If you wish to estimate the difference between the two population means correct to within 0.18, with probability equal to 0.90, how large should n₁ and n₂ be? Assume that you know σ₁² ≈ σ₂² ≈ 22.1.

(Round your answer up to the nearest whole number.)

n₁ = n₂ = ___observations

Answer 1