Which information do you need to use the critical values table?

Which information do you need to use the critical values table?

• A. A simple description of the data as mean and standard deviation.
• B. The observed p-value.
• C. The desired significance level, the number of participants, and whether the hypothesis is directional or non-directional.
• D. The confidence interval of the difference.

Answer: (C)

Critical values tables are about thresholds for deciding significance in hypothesis tests. To use them properly you need three things: the desired significance level (alpha), the sample size which determines the degrees of freedom, and whether the test is one-tailed (directional) or two-tailed (non-directional). These factors specify the exact cut-off value for your test statistic. If your calculated statistic exceeds that cut-off (in absolute terms for two-tailed tests), you reject the null hypothesis. Describing the data with a mean and standard deviation doesn’t tell you where the threshold is on the test distribution, so it isn’t what the critical values table requires. The observed p-value is another way to assess significance, but it’s a separate approach from reading a critical values table. Confidence intervals relate to estimating the parameter but aren’t the table you use to get a critical value.

Critical values tables are about thresholds for deciding significance in hypothesis tests. To use them properly you need three things: the desired significance level (alpha), the sample size which determines the degrees of freedom, and whether the test is one-tailed (directional) or two-tailed (non-directional). These factors specify the exact cut-off value for your test statistic. If your calculated statistic exceeds that cut-off (in absolute terms for two-tailed tests), you reject the null hypothesis.

Describing the data with a mean and standard deviation doesn’t tell you where the threshold is on the test distribution, so it isn’t what the critical values table requires. The observed p-value is another way to assess significance, but it’s a separate approach from reading a critical values table. Confidence intervals relate to estimating the parameter but aren’t the table you use to get a critical value.