Ch. 3: What Do Samples Tell Us?

D). 1/√n

What is the formula used to compute the margin of error for 95% confidence? A). 1/ n B). number of successes/ n C). √n/ 1 D). 1/√n

A). a higher confidence level will result in a larger range of values

Which of the following statements is true regarding the width of the range of values for your confidence interval when you use a higher confidence level? A). a higher confidence level will result in a larger range of values B). a higher confidence level will not affect the range of values C). a higher confidence level will result in a smaller range of values D). a higher confidence level will require a smaller sample

Blank: bias

You weigh yourself five times on a scale. The measurements are 155, 156, 152, 154, and 155. Your true weight is 170 pounds. Both __________ and variability are present in this sample

Blank: statistic

A researcher takes a simple random sample of 100 individuals to determine what percentage of the American public prefers Pepsi to Coke. The _________ is the proportion of the sample who prefers Pepsi to Coke

Blank: small

A good sampling method has small bias and ___________ variability

Blank: 95% of the sampling will be within plus or minus 3% from 80%

A news report states that 80% of Americans own a smartphone with a margin of error of 3% with a 95% confidence interval. A margin of error of 3% means ________

Blank: 0.02 The margin of error is 0.02, the margin of error tells us how close our estimate comes to the truth

A news reporter states that a study shows that 63% of people prefer vanilla ice cream to chocolate ice cream, plus or minus 2% points. The margin of error in this example is _________

C). 20,000 adults

A researcher is polling a random sample of 1000 adults living in a town. In order for the variability of this researcher's statistic to be unaffected by the population size, what must be the minimum total population of adults living in this town? A). 5,000 adults B). 150,000 adults C). 20,000 adults D). 10,000 adults

Blank: 0.125 Margin of error = 1/√n = 1/√64 = 0.125

A simple random sample of 64 people finds that 38 of the 64 like the television show "American Idol." The margin of error for 95% confidence is approximately 1/√n. The margin of error is __________. (Enter your answer to three decimal places.)

Blank: 64

A simple random sample of 64 people finds that 38 of the 64 like the television show "American Idol." The proportion of people in the sample who like "American Idol" is computed with 38/_____

Blank: 20

If the population is at least _________ times larger than the sample, then the population size doesn't matter in the variability of a statistic

Blank: 4

If we want to cut the margin error in half, we must use a sample _________ times as large

C). the sample size

In the formula used to compute the margin of error for 95% confidence, 1/√n, what does n represent? A). the population size B). the sample proportion C). the sample size D). the size of the confidence interval

D). the sample size

In the formula used to compute the margin of error for 95% confidence, 1/√n, what does n represent? A). the sample proportion B). the square root of the sample size C). 100 D). the sample size

Blank: sampling size

The decrease the margin of error, you must increase the ________

Blank: sample

The variability of a statistic from a random sample depends on the size of the __________

C). researcher 2

Two researchers are attempting to estimate the percentage of students who study more than 20 hours per week. Researcher 1 is sampling 100 students enrolled in an intro course with 500 students. Researcher 2 is sampling 100 students enrolled in an intro course with 1000 students. Which researcher will have a statistic with larger variability? A). variability will be the same B). researcher 1 C). researcher 2 D). it depends on the statistic