Worksheets8.4 Confidence Intervals for Proportions
Total questions: 6
Worksheet time: 46mins
Name
Class
Date
1.
A random sample of 100 WHS students found that 53 of them were in possession of a pencil. What is the p-hat for this sample?
a)
0.53
b)
0.5
c)
0.47
d)
1
2.
A survey of 80 recent fatal traffic accidents showed that 46 were alcohol-related. Find the 98% CI.
a)
(-30.01, 122.01)
b)
(45.87, 46.13)
c)
(.45, .70)
d)
(.29, .55)
3.
If 827 represents "no" voters out of 2584, construct a 95% confidence interval for the "no" group.
a)
[.300,.340]
b)
[.298,.342]
c)
[.302,.338]
d)
[.288,.352]
4.
Find the minimum sample size needed to be 4% within the true proportion if you are 95% confident and p-hat = 0.6
a)
12
b)
6
c)
961
d)
577
5.
A nutritionist found that in a sample of 80 families, 22% said they are apples at least once a week. Construct the 90% CI for the population proportion.
a)
(0.144, 0.296)
b)
(0.190, 0.250)
c)
(0.704, 0.856)
d)
(0.129, 0.311)
6.
A medical researcher wishes to determine the percentage of females who take vitamins. She wishes to be 99% confident that the estimate is with 2 percentage points of the population proportion. How large should the sample size be, at a minimum, if a recent study showed that 25% of females take vitamins?
a)
3012
b)
3111
c)
4011
d)
5613
100 %
