A study was conducted to validate a translated version of the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) questionnaire used with Spanish-speaking patients with hip or knee osteoarthritis. For the 76 women classified with severe hip pain, the WOMAC mean function score (on a scale from 0 to 100 with a higher number indicating less function) was 70.7 with a standard deviation of 14.6. We wish to know if we may conclude that the mean function score for a population of similar women subjects with severe hip pain is less than 75.
Let α = .01.
The critical value for the given α is ± 2.33.
The z equation is given below:
z= xbar - mue/ sigma upon route of n
5.1 Is this a two-tailed or one-tailed test?
5.2 Draw a graph depicting the critical value, rejection region, and non-rejection region.
5.3. State the null-hypothesis in words and in symbol.
5.4 State the alternative hypothesis in words and in symbol.
5.5 Based on the hypothesis being tested, should you use the critical value of -2.33 or 2.33 to compare against the computed z score to make the decision to reject or retain the null hypothesis.
5.6 Compute z statistic using the equation given above.
5.7 Comparing z statistics with the critical value, would you reject the null or retain the null hypothesis? In other words, does the z score lie in the rejection or non-rejection region?