Adults who broke their wrists were randomly divided into two groups. The "intervention" group was given exercises to do under the direction of a physiotherapist. The "control" group did not receive such intervention. The primary variable of interest was improvement in wrist extension, measured in degrees with a device called a goniometer, after 6 weeks. Consider a t test, with a directional alternative, to investigate the research hypothesis that the intervention improves wrist extension.

(a) Write the null hypothesis and the alternative hypothesis in symbols.
(b) Here is computer output for the t test. Explain what the P-value means in the context of this study.
t = 1.29, df = 40.8, p-value = 0.1022
alternative hypothesis: true difference in means is greater than 0
(c) If α = 0.10, what is your conclusion regarding H0?
(d) If the research hypothesis were non directional, how would your answer to part (c) change, if at all?

Transcribed Image Text:

Intervention Control Mean SD IT 25.6 17.5 27 20.5 9.0 20