Have an account?
Skip to Content
Build your own quiz
Suggestions for you
Mathematics
11th -
12thgrade
Chapter 7 Estimating a Parameter Final Exam Review
20 questions
Show Answers
See Preview
- 1. Multiple Choice
In a recent Gallup poll of randomly selected US adults, 75% said they would vote for a law that imposed term limits on members of the US Congress. The poll's margin of error was 4 percentage points at the 95% confidence level. This means that
the poll used a method that gets an answer within 4 percentage points of the truth about the population 95% of the time.
if Gallup takes another poll on this issue, the results of the second poll will lie between 71% and 79%.
there is convincing evidence that more than 79% of all US adults would vote for term limits.
Gallup can be 95% confident that between 71% and 79% of the adults in the sample would vote for term limits.
- 2. Multiple Choice
A political poll was conducted by calling land-line telephones. The researchers conducting the poll are concerned about the possibility of undercoverage because some people do not own a phone or own only a cell phone. Which of the following is the best way for them to correct for this source of bias?
Use a lower confidence level, such as 90%.
Use a higher confidence level, such as 99%.
Select a larger sample.
Throw this sample out and start over again with a better sampling method.
- 3. Multiple Choice
A 95% confidence interval for p, the proportion of all shoppers at a large grocery store who purchase cookies, is 0.236 to 0.282. The point estimate and margin of error for this interval are:
point estimate = 0.236; margin of error = 0.282
point estimate = 0.236; margin of error = 0.046
point estimate = 0.259; margin of error = 0.046
point estimate = 0.259; margin of error = 0.023
- 4. Multiple Choice
A quality control manager at a manufacturing plant wants to estimate the mean length of metal rods produced by a certain machine. The manager is deciding between a 95% confidence level and a 99% confidence level. Compared to a 95% CI, a 99% CI will be
narrower and would involve a larger risk of being incorrect.
wider and would involve a smaller risk of being incorrect.
narrower and would involve a smaller risk of being incorrect.
wider and would involve a larger risk of being incorrect.
- 5. Multiple Choice
A quality control manager at a manufacturing plant wants to estimate the mean length of metal rods produced by a certain machine. The researcher is deciding between a sample of size n = 500 and a sample of size n = 1000. Compared to suing a sample size of n = 500, a 95% CI based on a sample size of n = 1000 will be
narrower and would involve a larger risk of being incorrect.
narrower and would involve a smaller risk of being incorrect.
narrower and would involve the same risk of being incorrect.
wider and would involve a smaller risk of being incorrect.
- 6. Multiple Choice
Isabel selects a simple random sample of 28 seniors at her school and finds that 20 of them are planning to participate in the school's annual capture-the-flag game. She wants to construct a CI for p = the proportion of all seniors who plan to participate in the game, but she realizes she hasn't met all the conditions for constructing the interval. Which condition for this procedure has she failed to meet?
n ≥ 30
np̂ ≥ 10
n(1 - p̂) ≥ 10
The population must be approximately normal.
- 7. Multiple Choice
Most people can roll their tongues, but some can't. Suppose we are interesting in determining what proportion of people in a certain population can roll their tongues. We test a random sample of 80 people from this population and find that 64 can roll their tongues. The margin of error for a 95%CI for the true proportion of tongue rollers in this population is closest to
0.004
0.045
0.088
0.176
- 8. Multiple Choice
Many TV viewers express doubts about the validity of certain commercials. In an attempt to answer their critics, Times Group USA wishes to estimate the proportion of consumers who believe what is shown in Timex TV commercials. Let p represent the true proportion of consumers who believe what is shown in Timex TV commercials. Which of the following is the smallest number of consumers that Timex can survey to guarantee a margin of error of 0.05 or less at the 99% confidence level?
600
650
700
750
- 9. Multiple Choice
In checking conditions for constructing CIs for a population mean, it's important to plot the distribution of sample data. Each dotplot shoss the distribution of a sample from a different population. For which of the three samples would it be safe to construct a one-sample t interval for the population mean?
Sample X only
Sample Y only
Sample Y and Z
None of the samples
- 10. Multiple Choice
You want to calculate a 98% CI for a population mean from a sample of size n = 18. What is the appropriate critical value t*?
2.110
2.224
2.552
2.567
- 11. Multiple Choice
A study found that in a sample of 44 subjects, 9 of agree that children under 6 shouldn’t be taken to nice restaurants. Calculate a 95% confidence interval for p.
(0.105, 0.305)
(0.082, 0.318)
(0.117, 0.292)
(0.048, 0.361)
- 12. Multiple ChoiceA 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.(0.144, 0.296)(0.190, 0.250)(0.704, 0.856)(0.129, 0.311)
- 13. Multiple ChoiceIn a crash test of 15 troopers, collision repair costs are found to have a distribution that is approximately normal, with a mean of $1800 and a standard deviation of $950. Construct a 99% confidence interval for the repair cost.(1070, 2530)(1273, 2326)(1799, 1801)None of these.
- 14. Multiple ChoiceA random sample of 100 visitors to a popular theme park spent an average of $142 on the trip with a standard deviation of $47.5. Which of the following would be the 98% confidence interval for the mean money spent by all visitors to this theme park?($130.77, $153.23)($132.77, $151.43)($132.69, $151.31)($140.88, $143.12)
- 15. Multiple Choice
A sample of 20 cupcakes found the interval for average calories to be (150, 350). Which is the correct interpretation of the 95% confidence interval?
We are 95% confident that the true mean caloric content can be found with a sample of 150 to 350 cupcakes.
We are 95% confident that the interval (150, 350) captures the true average caloric content.
We are 95% confident that a sample of 20 cupcakes will find 250 calories per cupcake.
None of these are correct.
- 16. Multiple Choice
A quality control specialist at a glass factory must estimate the mean clarity rating for a new batch of glass using a sample of 18 glass sheets from the batch. Past investigations show that clarity ratings are normally distributed. The specialist decides to use a t-distribution rather than a z-distribution because ...
The t distribution is more accurate than a z distribution.
Clarity ratings for the entire bacth are normally distributed.
The t-distribution will create a narrower interval than z.
The standard deviation for the population is unknown.
- 17. 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.
- 18. Multiple ChoiceA biologist has taken a random sample of a specific type of fish from a large lake. A 95 percent confidence interval was calculated to be 6.8 ± 1.2 pounds. Which of the following is true?95 percent of all the fish in the lake weigh between 5.6 and 8 pounds.In repeated sampling, 95 percent of the sample proportions will fall within 5.6 and 8 pounds.In repeated sampling, the population mean fish weight will be captured in the interval 95% of the time.There is a 95% chance that the population mean weight is 6.8 pounds.
- 19. Multiple Choice
Find the critical value, z*, for 91% confidence.
1.70
1.34
0.18
-1.34
- 20. Multiple ChoiceWhat is the t value associated with 90% confidence and a sample size of 15?1.3411.3451.7611.753
- Answer choicesTagsAnswer choicesTags