Question 1

With a (an) __________ sample, every conceivable group of people of the required size has the same chance of being the selected sample.

Accepted Answer

The answer of With a (an) __________ sample, every conceivable...

Question 2

Suppose a random sample of people from your city found that 20% of the respondents own a cell phone, and the margin of error was 3%.In other words, you are confident that between 17% and 23% of all the people in your city own cell phones, based on this study.Suppose also that 1,000,000 people live in your city.Does this mean then that 200,000 people most likely own cell phones, plus or minus 30,000; or in other words, that between 170,000 and 230,000 people most likely own cell phones? (This was found by taking the results in percentage form and multiplying by the population size.)

Accepted Answer

The calculation correctly applies the percentage and margin of error to the total population, resulting in an accurate range of the number of people who own cell phones.

Question 3

What two things do you need in order to produce a simple random sample from the population?

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The answer of What two things do you need in...

Question 4

Suppose you sampled 2,500 people for a marketing survey, but your boss thinks that you should have sampled more, say 4,000 people, because he says the results would have been much more accurate, even under the tight budget and time constraints on the company.Using statistics, how would you convince your boss to agree with you?

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The answer of Suppose you sampled 2,500 people for a...

Question 5

As the number of units in the sample increases, the margin of error __________.

Accepted Answer

The answer of As the number of units in the...

Question 6

For Questions use the following narrative
Narrative: Exit poll
Suppose a recent election exit pollster reports that "Forty-eight percent of the voters polled said they voted for Candidate A.The margin of error for this survey is plus or minus 2.5 percentage points." Assume the exit poll was designed and conducted correctly.
-{Exit poll narrative} About how many people were sampled?

Accepted Answer

In order to calculate the margin of error, we need to know the sample size, which is not directly stated in the narrative. However, we can use the formula for margin of error to solve for n (sample size):
margin of error = z*sqrt(p*q/n)
where z is the z-score corresponding to the desired level of confidence (let's assume a 95% confidence level, so z = 1.96), p is the proportion of voters who said they voted for Candidate A (0.48), q is the complement of p (0.52), and n is the sample size.
Plugging in the given margin of error (0.025), we get:
0.025 = 1.96*sqrt(0.48*0.52/n)
Solving for n, we get:
n = (1.96^2)*(0.48*0.52)/(0.025^2) = 1,568
So the closest answer choice is B, 1,600.

Question 7

With a (an) __________ sample, everyone in the population must have a specified chance of making it into the sample.

Accepted Answer

The answer of With a (an) __________ sample, everyone in...

Question 8

Suppose you want to find out what percentage of students at your university would pay extra fees for the use of a new recreation center, and you want a simple random sample of 100 students.Suppose you go to the current recreation center and ask every 10th student who comes in the door to participate in your survey, until you have 100 people.Does this method of sampling give you a simple random sample? Explain your answer.

Accepted Answer

The answer of Suppose you want to find out what...

Question 9

Which is better, a survey of 50,000 people who participated on an Internet web site, or a survey of 5,000 people where a computer was used to randomly choose the survey participants?

Accepted Answer

The answer of Which is better, a survey of 50,000...

Question 10

With a random sample of 2,500 people, we usually get an estimate that is accurate to within what percent of the truth (using the general rule)?

Accepted Answer

The answer of With a random sample of 2,500 people,...

Question 11

What is the margin of error?

Accepted Answer

The margin of error is a statistic that measures the degree of possible error in the results of a survey. It is a way of quantifying the level of accuracy of the survey results by measuring the degree to which the sample responses may differ from the true population values. The margin of error is calculated based on the sample size and the level of confidence desired for the survey results. Therefore, C is the best choice as it correctly describes the margin of error.

Question 12

For Questions use the following narrative
Narrative: Exit poll
Suppose a recent election exit pollster reports that "Forty-eight percent of the voters polled said they voted for Candidate A.The margin of error for this survey is plus or minus 2.5 percentage points." Assume the exit poll was designed and conducted correctly.
-{Exit poll narrative} What can be concluded about Candidate A?

Accepted Answer

The correct conclusion is that we can be confident that between 45.5% and 50.5% of the voters voted for Candidate A, based on the reported 48% with a margin of error of ±2.5 percentage points. This range does not guarantee a win, as it does not definitively exceed 50%, making the election outcome uncertain.

Question 13

Assume you have a sampling frame of your entire population of interest, which is comprised of 100 people's names.Which of the following sources could not be used to select a truly simple random sample of 10 people from this population?

Accepted Answer

Putting the names in alphabetical order and taking the first 10 names on the list would not be a truly simple random sample because it would introduce bias based on the order in which the names appear on the list. The other methods would be truly random and unbiased.

Question 14

Suppose a recent election exit pollster reports that "Forty-eight percent of the voters polled said they voted for Candidate A.The margin of error for this survey is plus or minus 2.5 percentage points." Assume the exit poll was designed and conducted correctly.What percentage of all voters do you expect to vote for Candidate A? Give the most complete answer you can.

Accepted Answer

The answer of Suppose a recent election exit pollster reports...

Question 15

Suppose you have a herd of 100 cows and you need to select a simple random sample of 5 cows to test for a certain disease.You call the cows in for the evening, and pick the 5 that arrive first.Is this a simple random sample? Why or why not?

Accepted Answer

The answer of Suppose you have a herd of 100...

Question 16

The __________ can be applied to any percent reported regarding the sample to find an estimate of the percent of the population that would respond in the same way.

Accepted Answer

The answer of The __________ can be applied to any...

Question 17

Give three major advantages to using a (well designed and conducted) sample survey rather than a census.

Accepted Answer

The answer of Give three major advantages to using a...

Question 18

You have 15 employees working for you: Bob, Sue, Jim, Alex, DJ, Ann, Leslie, Eric, Deb, Tom, Clint, Richard, Tami, Ellen, and Katie.Use the following set of random numbers (generated from the computer program called Minitab) to take a simple random sample of 3 employees to serve on the donut committee: 1453131401146111619116112912015.Which employees got chosen for the donut committee? (Keep the employees in the order given when you assign numbers to them and do not start numbering with 0, start with 1.)

Accepted Answer

The random numbers correspond to the employee numbers: 14 (Ellen), 5 (Tami), and 1 (Bob).

Question 19

What is a probability sampling plan?

Accepted Answer

Probability sampling ensures that every member of the population has a specified, non-zero chance of being selected, which is the essence of option A.

Question 20

If you tried to phone someone who was selected to participate in a telephone survey, and you couldn't reach that person the first time, what should you do?

Accepted Answer

Keeping the person in the sample and continuing to try to reach them is the best option because it maintains the representativeness of the sample and reduces the risk of introducing bias. It is also possible that the person may eventually be reached and be able to participate in the survey.

Quiz 4: How to Get a Good Sample