49. A Gallup Poll found that only 28%of American adults expect to inherit money or valuable possessions from a relative. The poll’s margin of error was ±3percentage points at a 95% confidence level. This means that
(a) the poll used a method that gets an answer within 3%of the truth about the population 95% of the time.
(b) the percent of all adults who expect an inheritance is between 25%and 31%.
(c) if Gallup takes another poll on this issue, the results of the second poll will lie between 25%and 31%.
(d) there’s a 95% chance that the percent of all adults who expect an inheritance is between 25% and 31%.
(e) Gallup can be 95%confident that between 25% and 31% of the sample expect an inheritance

Short Answer

Expert verified

The option (a) is correct.

(a) the poll used a method that gets an answer within 3%of the truth about the population 95%of the time.

Step by step solution

01

Given information

The poll’s margin of error was ±3percentage points at a 95% confidence level. To determine the correct option from the given statement.

02

Explanation

(a) The confidence level technique indicates that the true population proportion is within 3% points of the sample mean.
As a result, the statement is correct.
(b) Only a 95%confidence level can guarantee that the population percentage is between 25and 31.
As a result, the statement is false.
(c) Confidence intervals fluctuate depending on the sample.
As a result, the statement is false.
(d) Either 0or 1is the probability. Since the population percentage is between 25and 31percent at the 95% confidence level.
As a result, the statement is false.
(e) The sample has a confidence level of 100%that expects an inheritance between 25and 31 percent .
As a result, the statement is false.
As a result, the right option is (a).

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Most popular questions from this chapter

Watching TV (6.1, 7.3) Choose a young person (aged 19to 25) at random and ask, “In the past seven days, how many days did you watch television?” Call the response Xfor short. Here is the probability distribution for X.

(a) What is the probability that X=7? Justify your answer.

(b) Calculate the mean of the random variable X. Interpret this value in context.

(c) Suppose that you asked 100randomly sele

cted young people (aged 19to 25) to respond to the question and found that the mean xof their responses was 4.96. Would this result surprise you? Justify your answer.

What critical value tfrom Table B would you use for a 90%confidence interval for the population mean based on an SRS of size 77? If possible, use technology to find a more accurate value of t. What advantage does the more accurate df provide?

I collect an SRS of size n from a population and compute a 95%confidence interval for the population proportion. Which of the following would produce a new confidence interval with larger width (larger margin of error) based on these same data?

(a) Use a larger confidence level.

(b) Use a smaller confidence level.

(c) Increase the sample size.

(d) Use the same confidence level, but compute the interval n times. Approximately5% of these intervals will be larger.

(e) Nothing can guarantee absolutely that you will get a larger interval. One can only say that the chance of obtaining a larger interval is 0.05.

High tuition costs Glenn wonders what proportion of the students at his school think that tuition is too high. He interviews an SRS of 50 of the 2400 students at his college. Thirty-eight of those interviewed think tuition is too high.

57. Critical values What critical value t* from Table B would you use for a confidence interval for the population mean in each of the following situations?
(a) A 95%confidence interval based on  n=10 observations.
(b) A 99%confidence interval from an SRS of 20 observations.

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