Question

The U.S. Department of Agriculture (USDA) uses sample surveys to estimate nationwide crop prices. Suppose that the USDA draws an SRS of corn producers in March and then a second, independent SRS of corn producers in September. In each survey, the USDA collects sales price per bushel of corn for each producer.

Summary statistics (prices per bushel)

Population	Sample size	Sample mean	Sample standard deviation
#1: corn prices, March	50	$3.82	$0.28
#2: corn prices, Sept.	62	$3.49	$0.34

Calculate the upper endpoint of the 99% confidence interval for the difference in population mean corn prices, μ 1 − μ 2. Use the simple method to estimate the number of degrees of freedom.

Group of answer choices

$0.21

$0.18

$0.37

$0.28

$0.48

Answer 1

Given that,

For March : n1 = 50, x1-bar = 3.82 and s1 = 0.28

For September : n2 = 62, x2-bar = 3.49 and s2 = 0.34

Using TI-83 plus calculator we get, the 99% confidence interval for the difference in population mean corn prices is, (0.18, 0.48)

Where, lower endpoint = $0.18 and

Upper endpoint = $0.48

Answer : $0.48

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