Hypothesis Test for Independent Groups Two Proportions In a recent local election, among 240 30 – 45 year olds, 45% voted and among 260 46 – 60 year olds, 50% voted. Do the data indicate that the proportion of 30 - 45 year olds who voted is less that the proportion of 46 – 60 year olds? Test at a 5% level of significance. Let A represent 30 – 45 year olds B represent 46 – 60 year olds Ho: pA = pB Ha: pA < pB

Hypothesis Test for Independent Groups Two Proportions PA – PB = difference between the proportions of 30 – 45 year olds and 46 – 60 year olds who voted in a recent local election. Distribution for the Test: Normal for Two Proportions

Hypothesis Test for Independent Groups Two Proportions Use 2-PropZTest. Test statistic: z = -1.12 Standardized score for pA’-pB’ = 0.45 – 0.5 = -.05 p-value: 0.1317

Hypothesis Test for Independent Groups Two Proportions Decision: Assume DO NOT REJECT Ho. Conclusion: There is NOT sufficient evidence to conclude that the proportion of 30-45 year olds who voted is less than the percentage of 46 – 60 year olds who voted.