Law/Crime Math HW

Module 9 Practice Problems (Chapter 10) A police department was interested in learning if men or women do better as a result of their training course. They administered a skills test to 60 newly trained officers: 30 males and 30 females. Use the data below to establish hypotheses and test them using a chi-square test. State the decision about whether the H0 is ultimately rejected or retained. Test Scores Excellent Good Unsatisfactory Customary Course 11 18 7 New Course 9 12 3 Step 1: State the H0 and the H1. Use statistical formulas, not an explanation. (1 points) H0 = H1 = Step 2: Identify the distribution and compute the degrees of freedom (df). (1 points) distribution = df = Step 3: Identify the critical value (right-tailed) of the test statistic and state the decision rule. (1 points) α = .05 critical value = decision rule = Step 4: Compute the obtained value of the test statistic. Use 3 decimal places where appropriate. (.25 each; 10 points total) Observed Values Customary Course New Course Row Marginal Excellent 11 9 20 Good 18 12 30 Unsatisfactory 7 3 10 Column Marginal 36 24 N = 60 Expected Values Customary Course New Course Row Marginal Excellent Good Unsatisfactory Column Marginal Cell 36 f oi 24 f oi − f ei f ei N = 60 ( foi − fei )2 ( f oi − f ei ) 2 f ei Excellent and Customary Excellent and New Good and Customary Good and New Unsatisfactory and Customary Unsatisfactory and New N = 60 N = 60 ∑=0 ∑= Step 5: Make a decision about the null and state the substantive conclusion. (3 points) It was stated that the null would be rejected if the obtained value of the test statistic exceeded ____________. The obtained value turned out to be ___________, so we will therefore ________________ the null hypothesis.