Here are the essential concepts you must grasp in order to answer the question correctly.
Critical Value
A critical value is a threshold that determines the boundary for rejecting the null hypothesis in hypothesis testing. It is derived from the chosen significance level (α) and the distribution of the test statistic. For a left-tailed t-test, the critical value is the point on the t-distribution that corresponds to the cumulative probability of α, indicating the cutoff for the rejection region.
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Critical Values: t-Distribution
Rejection Region
The rejection region is the range of values for the test statistic that leads to the rejection of the null hypothesis. In a left-tailed test, this region is located to the left of the critical value. If the calculated test statistic falls within this region, it suggests that the sample provides sufficient evidence to reject the null hypothesis in favor of the alternative hypothesis.
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t-Test
A t-test is a statistical test used to determine if there is a significant difference between the means of two groups, particularly when the sample size is small and the population standard deviation is unknown. The test uses the t-distribution, which accounts for the sample size and variability. In this case, a left-tailed t-test is employed to assess whether the sample mean is significantly less than a hypothesized population mean.
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Critical Values: t-Distribution