Question

• Step 1. Express the substantive question as two statistical hypotheses.
• Step 2.Choose a sample statistic to assess the statistical hypotheses. Draw the sampling distribution under the null hypothesis. Use p < .05 (unless another criterion is defended) as the criterion for statistical significance to determine the critical values.
• Step 3.If needed, compute the sample mean (M). Compute the standard error (SE). Transform a descriptive statistic into a test statistic (e.g., z_obsor t_obs). Determine if the p-value is < or > .05 under the null hypothesis (e.g., what the parameter is not). Determine any confidence intervals (e.g., estimate what the parameter is). Calculate an effect size  (e.g., standardized difference between the means).
• Step 4.Write the results in APA style.

1. A research team happens to know that male rats administered a placebo drug will spend μ = 5 minutes per hour grooming (σ = 6). They believe that male rats administered a low dose of the street drug ecstasy will spend less than 5 minutes per hour grooming. They chose 100 male rats, administered a low dose of ecstasy to each, then measured the number of minutes per hour each rat spent grooming. The mean of this sample was M= 4. The research question the researcher want to answer is: does administering a low dose of ecstasy affect the time spent grooming?

Answer 1