Deck 3: Stress

Question 1

The average class size this semester in the business school of a particular university is 38.1 students with a standard deviation of 12.9 students. The z-score for a class with 21 students is-------- .

A)0.80
B)- 1.33
C)1.51
D)0

Answer 1

- 1.33

Question 2

The interquartile range represents the middle ------- of a range.

A)75%
B)25%
C)50%
D)10%

Answer 2

50%

Question 3

Which of the following statements is not true concerning the attributes of z-scores?

A)z-scores are equal to zero for data values equal to the mean of the distribution.
B)z-scores are negative for data values below the mean of the distribution.
C)z-scores are positive for data values above the mean of the distribution.
D)z-scores can be positive or negative for data values above the mean of the distribution.

Answer 3

z-scores can be positive or negative for data values above the mean of the distribution.

Question 4

The--------- can found by subtracting the lowest value from the highest value in the data set.

A)range
B)variance
C)standard deviation
D)median

Question 5

The sample covariance can be equal to any value ________.

A)between -œ and +œ
B)other than zero
C)greater than or equal to zero
D)between - 1.0 and +1.0

Question 6

The sample ------- measures both the direction and strength of the linear relationship between two variables.

A)correlation coefficient
B)variance
C)covariance
D)z- score

Question 7

The sample correlation coefficient can be equal to any value------------- .

A)other than zero
B)between -œ and +œ
C)greater than or equal to zero
D)between - 1.0 and +1.0

Question 8

The first quartile represents the-------- percentile of the data set.

A)25th
B)10th
C)50th
D)75th

Question 9

A disadvantage of using the range as a measure of variability is that ---------.

A)the units of the range are the square of the original data set.
B)it is fairly difficult to calculate.
C)it is highly influenced by outliers.
D)all of the values in the data set are needed for the calculation.

Question 10

Comparing the consistency between two data sets when their means are very different is best done with the -------.

A)z-score
B)median
C)standard deviation
D)coefficient of variation

Question 11

-------- is a single value used to describe the center point of a data set.

A)Central tendency
B)Variation
C)Coefficient of variation
D)Relative position

Question 12

The following data represents the number of Sony TVs sold per day at a particular Costco over a random sample of five business days.
9 2 7 7 5
The mode of this sample is .

A)2
B)7
C)6
D)4

Question 13

Which one of the following statements is true for a left-skewed distribution?

A)The mean is roughly equal to the median.
B)The mean is less than the median.
C)The mean is greater than the mode.
D)The mean is greater than the median.

Question 14

The ------- is the most common and most important measure of variability in the field of statistics.

A)standard deviation
B)range
C)median
D)variance

Question 15

When working with grouped data, the ---------- is the value in the middle of the class and can be found by taking the average of the endpoints for each class.

A)median
B)midpoint
C)range
D)endpoint

Question 16

Which one of the following statements is true for a right-skewed distribution?

A)The mean is roughly equal to the median.
B)The mean is less than the median.
C)The mean is greater than the mode.
D)The mean is greater than the median.

Question 17

Suppose the dealer incentive per vehicle for Honda's Acura brand in 2012 is thought to be bell-shaped and symmetrical with a mean of $2,500 and a standard deviation of $300. Based in this information, what interval of dealer incentives would we expect approximately 99.7% of vehicles to fall within?

A)$1,900 to $3,100
B)$1,300 to $3,700
C)$2,200 to $2,800
D)$1,600 to $3,400

Question 18

The -------- is found by first determining the index point, i = 0.5(n), where n is the number of data points.

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

Question 19

The ---------- is the most commonly used measure of central tendency.

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

Question 20

The -------- is the best measure of central tendency for categorical data.

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

Question 21

The unit of measure for the variance is the same as the unit of measure for the original data.

Question 22

Suppose the nightly rate for a three-star hotel in Paris is thought to be bell-shaped and symmetrical with a mean of 160 euros and a standard deviation of 8 euros. The percentage of hotels with rates between 144 and 176 euros is

A)approximately 68.
B)approximately 95.
C)at least 75.
D)at least 89.

Question 23

Suppose the wait through immigration at JFK Airport in New York is thought to be bell-shaped and symmetrical with a mean of 22 minutes. It is known that 68 percent of travelers will spend between 16 and 28 minutes waiting to pass through immigration. The standard deviation for the wait time through immigration is

A)8 minutes.
B)9 minutes.
C)10 minutes.
D)6 minutes.

Question 24

The median is the ------- percentile in the data set.

A)100th
B)25th
C)50th
D)75th

Question 25

A random sample of 2008 used cars for sale on the market has an average mileage of 71,420 miles with a sample standard deviation of 9,470 miles. The z-score for a used car with 80,500 miles in this sample is ----------- .

A)0
B)0.43
C)0.96
D)- 1.22

Question 26

Because outliers are extreme values that could distort the analysis, they should always be eliminated from the data set.

Question 27

The ------- identifies the number of standard deviations a particular value is from the mean of its distribution.

A)z-score
B)median
C)empirical rule
D)coefficient of variation

Question 28

The average math SAT score for incoming freshman at a particular college is 535 with a standard deviation of 60. The coefficient of variation for SAT scores at this school is

A)11.2%.
B)18.0%.
C)13.9%.
D)15.6%.

Question 29

The ------ measures a distribution's standard deviation in terms of its percentage to the mean.

A)variance
B)z-score
C)coefficient of variation
D)median

Question 30

Measures of relative variation compare the position of one value in relation to other values in the data set.

Question 31

The sample ------ measures the direction of the linear relationship between two variables but does not measure the strength of the relationship.

A)variance
B)z- score
C)correlation coefficient
D)covariance

Question 32

Which one of the following statements is true for a symmetrical distribution?

A)The mean is greater than the median.
B)The mean is greater than the mode.
C)The mean is roughly equal to the median.
D)The mean is less than the median.

Question 33

When outliers are present in the data set, the ---------- is the best choice to measure central tendency.

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

Question 34

When you rely on the mean to summarize many data values, you lose important information about the original data.

Question 35

The ------ is the value that appears most often in a data set.

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

Question 36

Suppose the average price for new cars in 2012 has a mean of $30,100 and a standard deviation of $5,600. Based on this information, what interval of prices would we expect at least 89% of new car prices to fall within?

A)$24,500 to $35,700
B)$13,300 to $46,900
C)$18,900 to $41,300
D)$7,700 to $52,500

Question 37

Suppose the annual out-of-pocket health care expenses for retirees have a mean of $10,700 and a standard deviation of $2,500. The percentage of retirees with annual out-of-pocket health care costs between $5,700 and $15,700 is

A)approximately 95.
B)at least 89.
C)approximately 68.
D)at least 75.

Question 38

The ------------ is the value in the data set for which half the observations are higher and half the observations are lower.

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

Question 39

The average salary for a sales representative in a medical billing company is $46,600 with a standard deviation of $6,400. The coefficient of variation for salaries at this company is

A)16.4%.
B)13.7%.
C)9.0%.
D)11.7%.

Question 40

When comparing two samples, the smaller coefficient of variation indicates more consistency (or less variability)within the sample or population.

Question 41

The median of a data set is found by adding all the values in the data set and then dividing the result by the number of observations.

Question 42

A box-and-whisker plot displays the mean of the data set.

Question 43

When calculating a weighted mean, the weights need to sum to 1.0.

Question 44

Data Analysis ToolPak in Excel can be used to determine the mode for categorical data.

Question 45

In a quality control setting, the sample mean provides enough evidence to determine if a process is working properly.

Question 46

The average monthly rent for a two-bedroom apartment in City A is $820 with a standard deviation of $86. The average monthly rent for a two-bedroom apartment in City B is $790 with a standard deviation of $75. Based on this data, we can conclude that the rent for two-bedroom apartments in City A is more consistent when compared to City B.

Question 47

The mode is the most useful measure of central tendency for a data set.

Question 48

When calculating the sample mean of grouped data, the value represents an estimate of the true sample mean.

Question 49

When there is an even number of data values, the median is always the middle value in the data set.

Question 50

Chebyshev's Theorem states that for any number z greater than 1, the percent of the values that fall within z standard deviations from the mean will be at least (1 - 1 )× 100.
z2

Question 51

The sample covariance measures the direction of the linear relationship between two variables.

Question 52

The standard deviation of a data set can never be negative.

Question 53

Outliers are extreme values above or below the mean that require special consideration.

Question 54

The central tendency is where the majority of the data points can be found in a histogram.

Question 55

The five-number summary consists of a distribution's minimum value, the values for the first, second, and third quartiles, and maximum value.

Question 56

The mean of a data set is also known as the average value.

Question 57

The z-score has no units even though the original values will normally be expressed in units such as dollars, years, pounds, or calories.

Question 58

Chebyshev's Theorem only applies to bell-shaped curves that are relatively symmetrical.

Question 59

The percentile rank identifies the percentile of a particular value within a set of data.

Question 60

The range is a measure of central tendency.

Question 61

When sample means of two data sets are very different, comparing sample standard deviations can be misleading.

Question 62

If the data set does not have a mode, Data Analysis ToolPak in Excel displays "#N/A" in the spreadsheet cell.

Question 63

Using n - 1 in the denominator for the sample variance is a much better estimate of the true population variance when compared to dividing by n.

Question 64

Percentiles measure the approximate percentage of values in the data set that are below the value of interest.

Question 65

A negative sample covariance indicates that as one variable increases in value, the second variable tends to decrease.

Question 66

The sample variance is a biased estimator of the population variance because we would expect the average of many sample variances taken from a population would be equal to the true population variance.

Question 67

When there are an odd number of data values, the median is halfway between the two middle values in the data set.

Question 68

Percentile ranks are very useful when comparing values from two different data sets.

Question 69

The sample covariance measures the strength of the linear relationship between two variables.

Question 70

The sample correlation coefficient measures the strength and direction of the linear relationship between two variables.

Question 71

When using the index point, i, to determine the pth percentile of a data set, round i to the next whole number, if i = P (n)is not a whole number.
100

Question 72

When all of the data values in the sample are the same, the sample standard deviation equals 1.0.

Question 73

Some data sets may not have a mode.

Question 74

There can be more than one mode in a data set.

Question 75

According to the empirical rule, we would expect approximately 68, 95, and 99.7 percent of the values to fall within one, two, and three standard deviations above and below the mean respectively for all distributions.

Question 76

The sample standard deviation for grouped data provides an exact value for the sample standard deviation.

Question 77

Steve's grade on a recent statistics exam was an 85 on a scale of 0-100. Based on this information, we can conclude that Steve's grade was in the 85th percentile in his class.

Question 78

The MODE SNGL function in Excel will correctly identify more than one mode in a data set.

Question 79

A scatter plot is a graphical display showing the relative position of the three quartiles as a box on a number line along with the minimum and maximum values in the data set and any outliers.

Question 80

Data values that have z-scores above +1.0 or below - 1.0 are categorized as outliers.