Question

Question 8 Based on a study conducted last year, the incidence of heavy drinking among teenagers was 15%. You are in charge of monitoring this rate and conducted the annual survey. Of the 234 teenagers in the survey, 40 of them were heavy drinkers. If you want to know if the incidence rate has changed a. What are the null and alternate hypotheses? (2 marks) b. What is the test statistic to be used? (1 mark) c. Using a 5% significance level, can we conclude that the incidence rate has changed? (1 marks)

Answer 1

100 Given, ô = 15%: 15 = 3 = 0.15 Now, sample taken of n = 234 teenagers and sample proportion is = 40 Po = 20 117 Ê and Now, we want to test wheather - Po are squal or not. in a Null Hypothesis, Alternative Hypothesis, b. Test statistic to be used is 7. P- Po TES ZA N(o,)

test statistic - c. Now, calcuate the 0.15- z = 0.15 - 2017 Z 20 20 T7 117) y 234 s - 0.85 since this is the two tailed test- p value is; P(Z <0.85 or z>0.85) a P (Z L-0.85) + P(Z > 0185) - 0.19 766 + 0.19766 = 0.39532. MAY OTES : Since P value = 0.39532 is greater than significance Level 0.05 we can not reject the null Hypothesis
so we failed to reject the fact that the proportion are not changed.

So we can't conclude that the incidence rate has changed