The decision rule for rejecting the null hypothesis, considering the t-distribution, is of:
- |t| < 1.9801 -> do not reject the null hypothesis.
- |t| > 1.9801 -> reject the null hypothesis.
At the null hypothesis, it is tested if there is not enough evidence to conclude that the mean voltage for these two types of batteries is different, that is, the subtraction of the sample means is of zero, hence:
At the alternative hypothesis, it is tested if there is enough evidence to conclude that the mean voltage for these two types of batteries is different, that is, the subtraction of the sample means different of zero, hence:
We have a two-tailed test, as we are testing if the mean is different of a value.
Considering the significance level of 0.05, with 75 + 46 - 2 = 119 df, the critical value for the test is given as follows:
|t| = 1.9801.
Hence the decision rule is:
- |t| < 1.9801 -> do not reject the null hypothesis.
- |t| > 1.9801 -> reject the null hypothesis.
More can be learned about the t-distribution in the test of an hypothesis at brainly.com/question/13873630
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