Suppose a market analyst wants to determine the difference in the average price of 4 L of milk in Vancouver and Montreal. To do so, he takes a telephone survey of 31 randomly selected consumers in Vancouver. He first asks whether they have purchased 4 L of milk during the past two weeks. If they say no, he continues to select consumers until he selects n = 31 people who say yes. If they say yes, he asks them how much they paid for the milk. The analyst undertakes a similar survey in Montreal with 31 respondents. Using the resulting sample information that follows, compute a 99% confidence interval to estimate the difference in the mean price of 4 L of milk between the two cities. Assume the population variance for Vancouver is 0.12 and the population variance for Montreal is 0.06.

Transcribed Image Text:

Vancouver $3.77 $3.48 3.94 3.30 3.71 3.77 3.83 4.12 4.59 4.24 3.71 3.65 4.06 3.89 3.83 3.77 3.89 4.01 4.01 4.18 $3.59 3.59 3.53 3.65 3.77 4.01 4.36 3.89 4.12 3.94 4.01 $5.31 5.50 5.21 5.69 5.69 5.40 5.21 5.78 6.16 5.69 Montreal $5.69 $5.69 5.50 5.69 5.40 5.31 5.21 5.40 6.16 5.97 5.69 5.21 5.31 5.78 6.16 5.50 5.31 5.97 5.40 5.59 5.78