STAT 108 QUIZ 4 SOLUTION
A survey revealed that 47% of male drivers and 52% of female drivers never speed. Suppose
these results stem from samples of 1200 male drivers and 1000 female drivers, respectively.
Test the claim that the proportion of male drives who never speed doesn’t exceed that of
female drives. Conduct the test at the 10% significance level.
1. State the null and the alternative hypotheses.
a. 211210 :H ,:H
b. 211210 : ,: ppHppH males is sample 1; females, sample 2
c. 211210 p p:H ,pp:H
d. 211210 p p:H ,pp:H
2. Compute the test statistic.
a. -4.6766
b. – 0.2002
c. – 3.1092
d. -2.3358 2.33581/1000)12000.4927)(1/0.4927(10.52)/(0.47z
0.4927,1000)0))/(1200(0.52)(10000)((0.47)(12p
ˆ
3. Let 0
z denote the value of the test statistic in this example. What is the correct formula
for the P-value?
a. )( 0
zzP P-value reflects the sign of the alternative hypothesis (see Q1)
b. )z2P(z 0
d. Reject the alternative and conclude that the claim is true