WorksheetsConfidence Intervals
Total questions: 16
Worksheet time: 4hrs 0mins
A study found that in a sample of 44 subjects, 9 of agree that children under 6 shouldn’t be taken to nice restaurants.
The 95% confidence interval for p is (0.082, 0.318). Interpret this interval.
95% of the time the proportion of people who believe children under 6 shouldn't be taken to nice restaurants will be between 8.2% and 31.8%.
The population proportion of people who believe children under 6 shouldn't be taken to nice restaurants is between 8.2% and 31.8%.
The probability that the proportion of people who believe children under 6 shouldn't be taken to nice restaurants will be between 8.2% and 31.8% is 95%.
Based on this sample, I am 95% confident that the proportion of people who believe children under 6 shouldn't be taken to nice restaurants is between 8.2% and 31.8%.
A survey of 121 subjects found that 84 have suffered the symptoms of depression in the last year. Calculate a 90% confidence interval for p.
(0.612, 0.776)
(0.641, 0.748)
(0.780, 0.900)
(0.621, 0.759)
In a survey of 104 students, it was found that 79 went to the homecoming game this year.
Calculate a 99% confidence interval for p.
(0.652, 0.868)
(0.691, 0.829)
(0.678, 0.842(
(0.685, 0.895)
Which confidence would result in a wider interval (assuming nothing else changed), 91% or 97%?
97%, z* is larger for higher confidence intervals
97%, the standard error is larger for higher confidence intervals
91%, z* is larger for lower confidence intervals
91%, the standard error is smaller for lower confidence intervals
For a sample, the 95% confidence interval is (0.202, 0.482).
What is the point estimate, p̂, of this sample?
0.28
0.14
0.342
0.684
For a sample, the 95% confidence interval is (0.202, 0.482).
What is the margin of error of this sample?
0.28
0.14
0.342
0.684
A sample size of n = 64 is drawn from a population whose standard deviation is σ = 5.6.
Find the margin of error for a 99% confidence interval for µ.
1.799
1.798
1.803
An IQ test was given to a simple random sample of 75 students at a certain college. The sample mean score was 105.2. Scores on this test are known to have a standard deviation of 10. It is desired to construct a 90% confidence interval for the mean IQ scores of the students at the college.
What is the point estimate?
75
105.2
10
0.90
An IQ test was given to a simple random sample of 75 students at a certain college. The sample mean score was 105.2. Scores on this test are known to have a standard deviation of 10. It is desired to construct a 90% confidence interval for the mean IQ scores of the students at the college.
Find the critical value.
0.90
1.155
1.645
±1.645
An IQ test was given to a simple random sample of 75 students at a certain college. The sample mean score was 105.2. Scores on this test are known to have a standard deviation of 10. It is desired to construct a 90% confidence interval for the mean IQ scores of the students at the college.
Find the Margin of Error to two decimal places.
1.90
1.89
1.899
1.99
The lifetime of a certain type of batter is known to be normally distributed with a standard deviation of 20 hours. A sample of 50 batteries had a mean lifetime of 120.1 hours. It is desired to construct a 99% confidence interval for the mean lifetime of this type of battery.
What is the Confidence Interval to one decimal place?
(114.5, 125.6)
(112.8, 127.4)
(112.82, 127.38)
(114.56, 125.64)
If the 95% Confidence Interval for a population mean is (114.56, 125.54), then is it likely that the true population mean µ is greater than 130?
Yes
No
Not enough information
I have no idea what you're asking of me
True or False:
The more confident you want to be, the smaller your confidence interval will be.
True
False
True or False:
The larger your confidence interval is, the more sure (higher confidence level) you can be.
True
False
