12. (Two Samples) According to a survey, the mean price of gasoline in the United States was $1.20 per gallon in 1995 and $1.10 per gallon in 1994. (U.S. News & World Report, June 12, 1995). Suppose these means were based on random samples of 100 gasoline stations for 1995 and 120 gasoline stations for 1994. Also, assume that the sample standard deviations were $0.11 for 1995 and $0.10 for 1994. a. Construct a 98% confidence interval for the difference between the mean gasoline prices for 1995 & 1994. b. Test at the 1% significance level if the mean gasoline price was higher in 1995 than in 1994.

12. (Two Samples) According to a survey, the mean price of gasoline in the United States was $1.20 per gallon in 1995 and $1.10 per gallon in 1994. (U.S. News & World Report, June 12, 1995). Suppose these means were based on random samples of 100 gasoline stations for 1995 and 120 gasoline stations for 1994. Also, assume that the sample standard deviations were $0.11 for 1995 and $0.10 for 1994. a. Construct a 98% confidence interval for the difference between the mean gasoline prices for 1995 & 1994. b. Test at the 1% significance level if the mean gasoline price was higher in 1995 than in 1994.

Glencoe Algebra 1, Student Edition, 9780079039897, 0079039898, 2018

18th Edition

ISBN:9780079039897

Author:Carter

Publisher:Carter

Chapter10: Statistics

Section10.4: Distributions Of Data

Problem 19PFA

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