Supplement G: Report Writing for Hypothesis Tests A report on a hypothesis test (e.g., Binomial test, one-sample t-test) should include: · Introduction, including the alternative hypothesis for the study · Sample description, together with quoting the sample size and any other appropriate sample statistics · Comparison of values (if looking at a difference in means or proportions) · Comment on whether the observed difference (or relationship) is significant or not significant, quoting appropriate statistics · 95% confidence interval interpretation, quoting relevant values · Conclusion which relates back to the alternative hypothesis Note: sometimes the p-value will appear in SPSS output as .000. If that occurs, in a report it should be written as p < . 001 We will look in more specific detail at report writing for one-sample t-tests and Binomial tests below. But, in the later modules you will also see a similar general format as described above, when writing reports for other types of hypothesis tests. 1. Report writing for one-sample t-tests A report on a one-sample t-test should include: . Introduction, including the alternative hypothesis for the study · Sample description, including nature of the sample and mean, standard deviation and size of the sample · Comparison of sample mean with reference mean · Difference significant or not significant, quoting t, df and p · 95% confidence interval interpretation, quoting relevant values · Conclusion which relates back to the alternative hypothesis Supplement_G_Report_Writing_One_Sample_ttest_&_Binomial_Test Page 1 of 5
Example 1 A university lecturer believes that the average amount of sleep per night for students taking her unit differs from 8 hours per night. She took a random sample of her students and asked each student how much sleep they typically have per night. Use the SPSS output below to help write a report on the results of her study (testing at an alpha level of .05) One-Sample Statistics Hours sleep per night Hours sleep per night Report N Mean 15 7.2000 t -3.595 Std. Deviation .86189 Std. Error Mean .22254 One-Sample Test Test Value = 8 df Sig. (2-tailed) 14 .003 Mean Difference -. 80000 95% Confidence Interval of the Difference Lower -1.2773 Upper -. 3227 A university lecturer hypothesised that the average amount of sleep per night for students taking her unit differs from 8 hours per night. For a random sample of 15 university students taking her unit, the average amount of sleep per night was 7.20 hours (s = 0.86 hours). This is lower than 8 hours per night and a one- sample t-test shows this difference in mean hours sleep per night is significant, t(14) =3.60, p = . 003 The 95% confidence interval shows that average hours sleep per night for university students taking the instructor's unit is between 0.32 and 1.28 hours less than 8 hours. As expected, the average amount of sleep per night for students taking the instructor's unit differs from 8 hours, with her students on average sleeping less than 8 hours per night. Supplement_G_Report_Writing_One_Sample_ttest_&_Binomial_Test Page 2 of 5