Research Methods Module 4: Null Hypothesis Significance Testing

MBB2

Hypothesis

• is a predictive statement. When we conduct psychological research, we pose and test an experimental hypothesis

• An experimental hypothesis is a statement that predicts an effect. This effect might be one of

  • difference or association

• Experimental hypothesis are also called alternative hypothesis

Null hypothesis

• is also a prediction where it always predicts the one basic concept regardless of what is being investigated that nothing is happening. In other words, it is a hypothesis of no effect

  • No Difference or no association

• The experimental hypothesis is the alternative to the null hypothesis. Only one of these hypotheses can be supported by the research data

Statistical notation of null hypothesis

H₀

Statistical notation of alternative hypothesis

H₁

Null Hypothesis significance testing

• propose a null hypothesis that a population parameter (mean) has a particular value

• proceed assuming the null hypothesis is true

• determine the probability of the sample mean occurring if the null hypothesis is true

• if the probability of the sample mean occurring is small, reject the null hypothesis. If the probability is large, do not reject the null hypothesis