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- 1. Multiple Choice
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
- 2. Multiple Choice
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
2.575
1.645
1.96
- 3. Multiple Choice
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
- 4. Multiple Choice
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)
- 5. Multiple Choice
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
- 6. Multiple Choice
A population has a standard deviation of σ = 17.3. How large of a sample must be drawn so that a 95% confidence interval for µ will have a Margin of Error equal to 1.4?
586.6
587
586
585
- 7. Multiple Choice
Find the Critical Value for an 86% Confidence Level.
-1.48
1.48
1.282
-1.47
- 8. Multiple Choice
True or False:
The more confident you want to be, the smaller your confidence interval will be.
True
False
- 9. Multiple Choice
The amount added and subtracted to the sample statistic.
Margin of Error
Point Estimator
Statistic
Population
- 10. Multiple Choice
What is the margin of error for the interval (6.8 < μ <12.9 )?
9.85
3.05
3.50
6.8
- 11. Multiple Choice
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)
- 12. Multiple Choice
A preliminary study suggests that 17% of people agree on an issue. How large must your sample size be so you could be within ± 5% with 95% confidence?
217
30
2
152
- 13. Multiple Choice
You have no preliminary study to work from. How large must your sample size be so you could be within ± 3% of p at 90% confidence?
748
1068
11
1495
- 14. Multiple Choice
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
- 15. Multiple Choice
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
- 16. Multiple ChoiceA 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?0.530.50.471
- 17. Multiple Choice
Thirty randomly selected students took the calculus final. If the sample mean was 92 and the standard deviation was 9.4, construct a 99 percent confidence interval for the mean score of all students from which the sample was gathered.
89.08 < μ < 94.92
87.27 < μ < 96.73
87.29 < μ < 96.71
87.77 < μ < 96.23
- 18. Multiple Choice
Which of the following does NOT have an affect on the width of a confidence interval?
Sample mean
zc
Sample standard deviation
Sample size
- 19. Multiple ChoiceWhich of the following changes to a study would result in a narrower confidence interval?increasing the confidence level, increasing the sample sizedecreasing the confidence level, decreasing the sample sizeincreasing the confidence level, decreasing the sample sizedecreasing the confidence level, increasing the sample size.
- 20. Multiple Choice
The football coach randomly selected ten players and timed how long each player took to perform a certain drill. The times (in minutes) were: 13.2, 5.1, 7.5, 8.0, 12.7, 7.6, 13.8, 14.5, 7.7, and 10.5. Determine a 95 percent confidence interval for the mean time for all players.
12.30 < μ < 7.82
7.82 < μ < 12.30
7.74 < μ < 12.46
12.40 < μ < 7.72
- 21. Multiple ChoiceGiven the same mean, SD, and sample size, a confidence interval of 80% would be wider than a confidence interval of 90%TrueFalse
- 22. Multiple ChoiceA random sample of 85 sixth-graders in a large city take a course designed to improve scores on a reading comprehension test. Based on this sample, a 90% confidence interval for the mean improvement in test scores for all sixth-graders in the city taking this course is found to be (12.6, 14.8). Which of the following are the sample mean and margin of error on which this interval is based?Sample Mean = 13.7; Margin of Error = 1.1Sample mean = 13.7; Margin of Error = 2.2Sample mean is unknown; Margin of Error = 2.2
- 23. Multiple ChoiceA random sample of size n is collected from a Normally distributed population with standard deviation σ. Using these data, a confidence interval is computed for the mean of the population. Which of the following actions would produce a new confidence interval with a smaller width (smaller margin of error), assuming that the same data were used?Using a higher confidence levelUsing a lower confidence levelUsing a smaller sample size n
- 24. Multiple Choice
Which of the following would result in a smaller minimum sample size?
Increasing the confidence level
Not having a preliminary estimate for p-hat
Decreasing the confidence level
Decreasing the margin of error
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