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Statistical Inference About 2 Population Sample Assignment

Questions: - A consumer test group wants to determine the difference is gasoline mileage of cars using regular unleaded gas and cars using premium unleaded gas. Researches for the group divided a fleet of 100 cars or the same make in half and tested each car on one tank of gas. Fifty of the cars were filled with regular unleaded gas and 50 were filled with premium unleaded gas. The sample average for the regular gasoline group was 21.45 miles per gallon (mpg), and the sample average for the premium gasoline group was 24.6 mpg. Assume that the population standard deviation of the regular unleaded gas population is 3.46 mpg, and that the population standard deviation of the regular unleaded gas population is 2.99 mpg. Construct a 95% confidence interval to estimate the difference in the mean gas mileage between the cars using regular gasoline and the cars using premium gasoline.

Solution: - The z value for 95% confidence intervals is 1.96. the other sample information follows.

Regular                Premium
n_r = 50                    n_p = 50
x_r = 21.45                x_p = 24.6
α = 3.46                α_p = 2.99

Based on this information, the confidence interval is



We are 95% confident that the actual difference is mean gasoline mileage between the two types of gasoline is between – 1.88 mpg and -4.42 mpg. The point estimate is -3.15mpg.

Other Sample Assignments in Statistics Homework Assignment :

Continious Distribution	Descrete Distributions
Descriptive Statistics	Nonparamatric Statistics
Probability	Sampling And Sampling Distribution
Statistical Inference Estimation For Single Popula	Simple Regression Analysis
Statistical Inference About 2 Population	Time Series Forcasting Index Number
Statistical Quality Control	Correlation
Index Number	Larger Sample Mean Proportions
Non Parametric Test	Probability Theory
Sampling Distribution	Simple and Multiple Linear Regression Analysis
Unvariate Analysis

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