An industrial plant wants to determine which of two types of fuel, electric or gas, is more cost efficient (measured in cost per unit of energy). Independent random samples were taken of plants using electricity and plants using gas. These samples consisted of 15 plants using electricity, which had a mean cost per unit of $66.7 and standard deviation of $8.75 , and 8 plants using gas, which had a mean of $59.4 and standard deviation of $8.07 . Assume that the populations of costs per unit are normally distributed for each type of fuel, and assume that the variances of these populations are equal. Can we conclude, at the 0.1 level of significance, that the mean cost per unit for plants using electricity, μ1 , is greater than the mean cost per unit for plants using gas, μ2 ? Perform a one-tailed test. The null hypothesis: H0: The alternative hypothesis: H1: The type of test statistic: (Choose one)ZtChi squareF The value of the test statistic:(Round to at least three decimal places.) The p-value:(Round to at least three decimal places.) Can we conclude that the mean cost per unit for plants using electricity is greater than the mean cost per unit for plants using gas? Yes No
An industrial plant wants to determine which of two types of fuel, electric or gas, is more cost efficient (measured in cost per unit of energy). Independent random samples were taken of plants using electricity and plants using gas. These samples consisted of
plants using electricity, which had a mean cost per unit of
and standard deviation of
, and
plants using gas, which had a mean of
and standard deviation of
. Assume that the populations of costs per unit are
level of significance, that the mean cost per unit for plants using electricity,
, is greater than the mean cost per unit for plants using gas,
?
Perform a one-tailed test.
The null hypothesis: |
H0:
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The alternative hypothesis: |
H1:
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The type of test statistic: | (Choose one)ZtChi squareF | |||
The value of the test statistic: (Round to at least three decimal places.) |
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The p-value: (Round to at least three decimal places.) |
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Can we conclude that the mean cost per unit for plants using electricity is greater than the mean cost per unit for plants using gas? |
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