Question

PSY230 STATISTICS WHAT IS POWER? describe the factors that can result in inadequate power. For each factor- suggest a way to increase the power of a potential study. Lastly, which one of the above factors is the simplest to manipulate, how do researchers determine the necessary value of that factor to obtain the desired power?

Answer 1

First of all for understanding power, we should understand the Type II error. A type II error occurs when one fails to reject a null hypothesis that is actually false. The probability of not doing a type II error is the power of a test.

Basically power of a test is the probability of rejecting a false null hypothesis.

Small sample size can give you inadequate power.

Large difference between the true population value and the value specified in the Null hypothesis which is also called effects size can give you a bad power.

In addition, Power of a test can reduce when you reduce the significance level of your test.

Researchers can increase the sample size if they want to increase the power. Significance level comes with a tradeoff. Effect size can be manipulated too. Most important is the sample size