Which term represents the probability of making a Type I error?

Which term represents the probability of making a Type I error?

• A. Power
• B. Level of significance
• C. Confidence Level
• D. Degrees of Freedom

Answer: (B)

The probability of making a Type I error is the level of significance, often written as alpha. This is the threshold you set for how extreme your data must be to reject the null hypothesis, and it directly controls the risk of a false positive when the null is actually true. For example, setting alpha to 0.05 means you’re willing to reject the null in about 5% of repeated trials when the null is true. This concept is different from power, which is the chance of correctly detecting a true effect; from the confidence level, which relates to the long-run reliability of confidence intervals; and from degrees of freedom, which relate to the data and the distribution of the test statistic.

The probability of making a Type I error is the level of significance, often written as alpha. This is the threshold you set for how extreme your data must be to reject the null hypothesis, and it directly controls the risk of a false positive when the null is actually true. For example, setting alpha to 0.05 means you’re willing to reject the null in about 5% of repeated trials when the null is true. This concept is different from power, which is the chance of correctly detecting a true effect; from the confidence level, which relates to the long-run reliability of confidence intervals; and from degrees of freedom, which relate to the data and the distribution of the test statistic.