Deck 6: Statistics

Question 1

An auto dealer's sales numbers are shown in the table below. Find the median price for the cars sold in July.

A)$25,000
B)$20,000
C)$15,000
D)$22,500

Answer 1

C

Question 2

Half of students in a class got 77% on a test while the remaining half got 83%. What is the standard deviation of the test scores for the class?

A)2.45
B)4.24
C)3.00
D)1.71

Answer 2

C

Question 3

A(n) _______________ is a data point that is significantly different from most of the data.

A)foreigner
B)outlier
C)quartile
D)anomaly

Answer 3

B

Question 4

If data are normally distributed, which of the following is NOT true?

A)The distribution graph is a bell-shaped curve.
B)The mean and median are the same.
C)Most of the data tend to be clustered relatively far from the mean.
D)The data are symmetrically distributed above and below the mean.

Question 5

Michael's five test scores in his physics class were 75, 67, 88, 91, and 84. What was his mean test score?

A)84
B)81
C)79
D)88

Question 6

The _______________ quartile is the median of the upper half of the numbers in a list.

A)first
B)second
C)third
D)fourth

Question 7

The _______________ of a set of data measures the frequency with which each data point occurs.

A)distribution
B)quartiles
C)mean
D)spread

Question 8

A _______________ is a pictorial display of the five-number summary.

A)histogram
B)boxplot
C)scatterplot
D)line graph

Question 9

XYZ Corporation recorded the number of employee absences each week over a period of 10 weeks. The result is the data list 5, 3, 4, 1, 4, 7, 2, 6, 3, 5. Find the mean number of absences each week.

A)3
B)4
C)5
D)6

Question 10

An auto dealer's sales numbers are shown in the table below. Find the mean price for the cars sold in June.

A)$20,000.00
B)$18,679.25
C)$18,737.86
D)$19,047.62

Question 11

If a number in a data set occurs more frequently than any other number, it is called the _______________ of the data.

A)mean
B)median
C)mode
D)average

Question 12

The median of a list of numbers arranged from smallest to largest is the _______________ number.

A)first
B)last
C)middle
D)average

Question 13

An auto dealer's sales numbers are shown in the table below. Find the mode price for the cars sold in August.

A)$25,000
B)$20,000
C)$15,000
D)$17,500

Question 14

The standard deviation is a measure of how much the data are spread out from the mean.

A)median
B)mean
C)mode
D)standard deviation

Question 15

The standard deviation is a measure of how much the data are spread out from the mean.

Question 16

The mean of a list of numbers is the product of the numbers divided by the number of entries in the list.

Question 17

For a certain number of vehicles, their mileages are recorded and summarized using a boxplot. Which of the following is NOT correct?

A)The mean is around 22.5.
B)The difference between the maximum and minimum is about 20.
C)The spread from the first quartile to the third quartile is about 8.
D)The median is closer to the first quartile than the third quartile.

Question 18

XYZ Corporation recorded the number of employee absences each week over a period of 10 weeks. The result is the data list 5, 3, 4, 1, 4, 7, 2, 6, 3, 5. Find the standard deviation of the number of absences each week.

A)0.55
B)1.00
C)1.73
D)1.83

Question 19

Michael's five test scores in his physics class were 75, 67, 88, 91, and 84. What was his median test score?

A)84
B)81
C)79
D)88

Question 20

Suppose that every student in your class scored 75% on their first test. Find the standard deviation of the exam scores.

A)0
B)1
C)0.75
D)0.87

Question 21

A six-year study in a certain country found that birth weights of newborns were normally distributed, with a mean of 3758 grams and a standard deviation of 496 grams. What is the z-score for a newborn weighing 4000 grams?

A)0.81
B)0.73
C)0.61
D)0.49

Question 22

To find the confidence interval, adjust the result of the poll by adding and subtracting the ______________.

A)average
B)margin of error
C)confidence level
D)median

Question 23

For a 95% level of confidence and a sample size of n, the margin of error is approximately:

A)
B)
C)
D)

Question 24

It is found that the number of raisins in a box of a popular cereal is normally distributed, with a mean of 142 raisins per box and a standard deviation of 11 raisins. Your cereal box has 159 raisins. What is the z-score for this box of cereal?

A)2.71
B)2.47
C)1.55
D)1.74

Question 25

It is known that in the absence of treatment, 68% of the patients with a certain illness will improve. The central limit theorem tells us that the percentages of patients in groups of 500 that improve in the absence of treatment are approximately normally distributed. Find the mean of the normal distribution given by the central limit theorem.

A)72%
B)59%
C)34%
D)68%

Question 26

The _______________ for a number relative to a list of data is the percentage of data points that are less than or equal to that number.

A)z-score
B)percentile
C)quartile
D)t-score

Question 27

For data points above the mean, the z-score is _______________.

A)positive
B)negative
C)zero
D)undefined

Question 28

Ridge counts on fingerprints are approximately normally distributed, with a mean of about 140 and a standard deviation of 50. Which of the following intervals will contain 47.5% of the population?

A)140 ± 50 ridges
B)90 ± 100 ridges
C)140 ± 100 ridges
D)190 ± 50 ridges

Question 29

Suppose we toss 150 fair coins and record the percentage of heads. According to the central limit theorem, the percentages of heads resulting from such experiments are approximately normally distributed. Find the standard deviation of this normal distribution.

A)5.0%
B)4.5%
C)4.1%
D)3.7%

Question 30

If we construct a confidence interval from the result of a poll, then the interval should contain the true result.

Question 31

The IQ (Intelligence Quotient) test scores are normally distributed and are scaled to a mean of 100 and a standard deviation of 15. If a person's IQ has a z-score of 1.8, what is the IQ score?

A)124
B)127
C)129
D)131

Question 32

Ridge counts on fingerprints are approximately normally distributed, with a mean of about 140 and a standard deviation of 50. It then follows that 68% of the population will have:

A)140 ± 50 ridges
B)140 ± 68 ridges
C)140 ± 100 ridges
D)140 ± 150 ridges

Question 33

The _______________ of a poll tells the percentage of such polls in which the confidence interval includes the true result.

A)margin of error
B)interpolation
C)confidence level
D)extrapolation

Question 34

The average yearly high temperature in a certain city is recorded. It is found that the mean temperature is 70.2°F with a standard deviation of 8.2°F. Assuming that the data are normally distributed, in what range should 95% of the data lie?

A)53.8°F - 86.6°F
B)62.0°F - 78.4°F
C)47.7°F - 59.9°F
D)45.6°F - 94.8°F

Question 35

It is known that in the absence of treatment, 68% of the patients with a certain illness will improve. The central limit theorem tells us that the percentages of patients in groups of 500 that improve in the absence of treatment are approximately normally distributed. Find the standard deviation of the normal distribution given by the central limit theorem.

A)2.1%
B)2.5%
C)3.2%
D)4.4%

Question 36

If a set of data is normally distributed, then about _______________ of the data lie within one standard deviation below the mean.

A)34%
B)47.5%
C)68%
D)95%

Question 37

The average yearly high temperature in a certain city is recorded. It is found that the mean temperature is 70.2°F with a standard deviation of 8.2°F. Assuming that the data are normally distributed, in what range should 68% of the data lie?

A)53.8°F - 86.6°F
B)62.0°F - 78.4°F
C)47.7°F - 59.9°F
D)45.6°F - 94.8°F

Question 38

If a set of data is normally distributed, then about _______________ of the data lie within two standard deviations above the mean.

A)34%
B)47.5%
C)68%
D)95%

Question 39

Assume we know that 20% of Americans suffer from a certain type of allergy. Suppose we take a random sample of 8000 Americans and record the percentage who suffer from this allergy. What guarantees that percentages from such a survey will be normally distributed?

A)The law of large numbers
B)The general survey theorem
C)The central limit theorem
D)The law of survey

Question 40

The z-score can be used to compare the relative location of values from the sets of data with different distribution. Suppose that a Statistics class gave two midterms so far. If you scored 83 on Midterm 1 and 85 on Midterm 2, which score is relatively higher than the other? Use the information below.

A)83
B)85
C)They are equivalent.
D)Not enough information.

Question 41

The correlation coefficient always lies between -1 and 1 inclusive.

Question 42

A news article refers to a poll that "surveyed 978 registered voters and carries a plus or minus 3.5% margin of error." Assuming a 95% confidence interval, compute the true margin of error.

A)3.2%
B)3.3%
C)3.4%
D)3.5%

Question 43

A polling organization conducts a poll by making a random survey of 1250 people. Estimate the margin of error at a confidence interval of 95%.

A)1.25%
B)2.50%
C)2.83%
D)2.95%

Question 44

The results of a clinical trial are considered to be statistically significant if they are unlikely to have occurred by chance alone.

Question 45

By what factor should the sample size in a poll be increased in order to cut the margin of error in half?

A)2
B)4
C)8
D)9

Question 46

If we conduct a poll of 1600 people, then what is the approximate margin of error for a 95% confidence interval?

A)2.5%
B)2.8%
C)3.1%
D)3.4%

Question 47

A poll on a cigarette tax increase includes the following: "In the past decade, cigarette smokers have been targeted five times for tax increases. Do you favor another cigarette tax increase?" Does this question show any bias?

A)Yes, it is biased against the tax increase.
B)Yes, it is biased in favor of the tax increase.
C)No, it is not biased.
D)No, it is unrelated to the tax increase.

Question 48

For a 90% confidence level and a sample size of n, the margin of error is approximately %. How many people should we survey if we'd like to have a 3% margin of error with a 90% confidence interval?

A)1000
B)748
C)692
D)500

Question 49

A polling organization conducts a poll by making a random survey and is willing to accept a margin of error of 4% at a confidence level of 95%. What should the sample size be?

A)625
B)750
C)380
D)500

Question 50

For a 90% confidence level and a sample size of n, the margin of error is approximately %. If you survey 1500 people, what is the margin of error for a 90% confidence interval?

A)2.1%
B)2.3%
C)2.5%
D)2.7%

Question 51

We say that two numerical variables are _______________ correlated if an increase in one of them accompanies a decrease in the other.

A)positively
B)negatively
C)neutrally
D)not

Question 52

The _______________ measures the probability that the outcome of a clinical trial would occur by chance alone if the treatment had no effect.

A)level of significance
B)p-value
C)odd probability
D)critical value

Question 53

A polling organization conducts a poll by making a random survey and is willing to accept a margin of error of 3.5% at a confidence level of 95%. What should the sample size be?

A)350
B)763
C)817
D)1023

Question 54

A correlation coefficient whose magnitude is between 0.5 and 0.8 indicates _______________ linear correlation.

A)no
B)weak
C)moderate
D)strong

Question 55

A poll on a cigarette tax increase includes the following: "Last year, cigarette taxes funded an extra one hundred child healthcare projects in the state. Do you favor a cigarette tax increase?" Does this question show any bias?

A)Yes, it is biased against the tax increase.
B)Yes, it is biased in favor of the tax increase.
C)No, it is not biased.
D)No, it is unrelated to the tax increase.

Question 56

A _______________ p-value is usually interpreted as evidence that the event in question is unlikely to be due to chance alone.

A)large
B)small
C)negative
D)positive

Question 57

A correlation coefficient near 0 indicates little if any _______________ correlation.

A)positive
B)negative
C)linear
D)nonlinear

Question 58

In a clinical trial, participants are randomly divided into two groups. The group given the drug or treatment to be tested is called the test group while the other group given placebo is called the __________ group.

A)comparison
B)control
C)dummy
D)reference

Question 59

A polling organization conducts a poll by making a random survey of 2500 people. Estimate the margin of error at a confidence interval of 95%.

A)1.5%
B)2.0%
C)2.5%
D)3.0%

Question 60

For a 95% level of confidence, the sample size needed to get a margin of error of m percentage points can be approximated using:

A)
B)
C)
D)

Question 61

Determine which pair of variables is uncorrelated.

A)The daily average temperature and the sales of cell phones.
B)The daily average temperature and the sales of overcoats.
C)The daily average temperature and the sales of shorts.
D)The daily average temperature and the sales of gloves.

Question 62

Suppose that for a certain illness, the probability is 40% that a given patient will improve without treatment. Then the probability that at least n out of 20 patients will improve without treatment is given in the following table: We gave an experimental drug to 20 patients who have the illness and 11 patients showed improvement. What is the p-value?

A)0.25
B)0.13
C)0.06
D)0.02

Question 63

Suppose that for a certain illness, the probability is 40% that a given patient will improve without treatment. Then the probability that at least n out of 20 patients will improve without treatment is given in the following table: Suppose we count the test significant if the p-value is 0.05 or less. How many patients must show improvement in order to make the test statistically significant?

A)11
B)12
C)13
D)14

Question 64

Consider the pair of variables: Time you spend running on a track and calories you will burn. These variables are:

A)positively correlated.
B)negatively correlated.
C)uncorrelated.
D)statistically significant.

Question 65

Determine which pair of variables is positively correlated.

A)Your grades and the number of hours a week you study.
B)Your grades and the number of hours a week you play video games.
C)Your grades and the number of sandwiches you eat in a week.
D)Your grades and the number of hats you wear in a week.

Question 66

Determine which figure shows the weakest linear relationship.

A)
B)
C)
D)

Question 67

Consider the pair of variables: Intensity of a light bulb and your distance from the light bulb. The variables are:

A)positively correlated.
B)negatively correlated.
C)uncorrelated.
D)statistically significant.

Question 68

Consider the pair of variables: The number of touchdowns thrown by Tom Brady and the number of bills in your wallet. These variables are:

A)positively correlated.
B)negatively correlated.
C)uncorrelated.
D)statistically significant.

Question 69

Determine which figure shows the strongest linear relationship.

A)
B)
C)
D)