Deck 2: Descriptive Statistics

Question 1

The box-and-whiskers display is a graphical portrayal of data sets that depict both the central tendency and variability of the data.

Answer 1

True

Question 2

The mode is the measurement in a sample or population that occurs most frequently.

Answer 2

True

Question 3

It is appropriate to use the Empirical Rule to describe a population that is extremely skewed.

Answer 3

False

Question 4

The population mean is the average of the population measurements.

Question 5

The median is the measure of central tendency that divides a population or sample into four equal parts.

Question 6

A normal population has 99.73 percent of the population measurements within _____ standard deviations of the mean.

A)one
B)two
C)three
D)four
E)five

Question 7

If there are 7 classes in a frequency distribution,then the fourth class will always contain the median.

Question 8

A Pareto chart is a type of histogram.

Question 9

A number calculated using the sample measurements that describes some aspect of the sample is a sample ____________.

A)mean
B)variance
C)statistic
D)parameter
E)scale

Question 10

The median is said to be resistant to extreme values.

Question 11

An independent variable is a variable that can be used to describe,predict,or control a dependent variable.

Question 12

The median is the value below which approximately 50 percent of the measurements lie.

Question 13

In a symmetric population,the median equals the mean.

Question 14

The relative frequency is the frequency of a class divided by the total number of measurements.

Question 15

The population mean is a point estimate of the sample mean.

Question 16

A stem-and-leaf display is a graphical portrayal of a data set that shows the data set's overall pattern of variation.

Question 17

The range of set of measurements is the largest measurement plus the small measurement.

Question 18

Range is a better measure of variation than standard deviation.

Question 19

When establishing the classes for a frequency table it is generally agreed that the more classes you use the better your frequency table will be.

Question 20

The population variance is the average of the squared deviations of the individual population measurements from the population mean.

Question 21

A stem-and-leaf display is best used to _____

A)provide a point estimate of the variability in the population.
B)provide a point estimate of the central tendency in the population.
C)display the shape of the distribution of measurements.
D)reduce sampling bias.
E)represent the distribution of qualitative data.

Question 22

Which percentile describes the third quartile,Q3?

A)25^th
B)50^th
C)75^th
D)100^th
E)125^th

Question 23

If the mean,median,and mode for a given population are all equal,then we know that its distribution is _____.

A)bimodal
B)skewed to the right
C)symmetric
D)skewed to the left

Question 24

All of the following can be used to describe quantitative data with the exception of a _____.

A)histogram
B)stem-and-leaf display
C)dot plot
D)pie chart
E)scatter plot

Question 25

A ______________ shows the relationship between two quantitative variables.

A)box-and-whiskers display
B)bar chart
C)histogram
D)scatter plot
E)pie chart

Question 26

A ______________ displays the frequency of each group with qualitative data and a __________ displays the frequency of each group with quantitative data.

A)histogram,stem-and-leaf display
B)bar chart,histogram
C)scatter plot,bar chart
D)stem-and-leaf display,pie chart
E)scatter plot,pie chart

Question 27

If a population distribution is positively skewed (i.e.skewed to the right),then,given a random sample from that population,one would expect that the ______________.

A)median would be greater than the mean
B)mode would be equal to the mean
C)median would never equal the mode
D)median would be equal to the mean
E)median would be less than the mean

Question 28

When grouping a large sample of items into classes,the _____ is a better tool than the ____.

A)histogram,stem-and-leaf display
B)box-and-whiskers display,histogram
C)stem-and-leaf display,histogram
D)scatter plot,box-and-whiskers display
E)box-and-whiskers display,scatter plot

Question 29

If one intends to compare the relative variation between two samples involving two different quantitative variables with different measurement scales,then the most appropriate way is to compare the __________ from the two samples.

A)standard deviations
B)variances
C)coefficients of variation
D)ranges
E)interquartile ranges

Question 30

Which of the following graphs is used to summarize qualitative data?

A)Histogram
B)Bar Chart
C)Time series plot
D)Stem-and-leaf display
E)Scatter plot

Question 31

Which of the following is influenced the least by the occurrence of extreme values in a sample?

A)Mean
B)Median
C)Mode
D)Range
E)Variance

Question 32

_____________ and ____________ are used to describe qualitative (categorical)data.

A)Stem-and- leaf displays;scatter plots.
B)Scatter plots;and box-and-whiskers displays
C)Box-and-whiskers displays;bar charts
D)Bar charts;pie charts
E)Pie charts;histograms

Question 33

Which percentile describes the first quartile,Q1?

A)25^th
B)50^th
C)75^th
D)100^th
E)125^th

Question 34

All of the following are measures of central tendency except the _____.

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

Question 35

If a statistics course is determined by three exams.Exam 1 is worth 25% of the course grade.Exam 2 is worth 35% of the course grade.Exam 3 is worth 40% of the course grade.Calculate the term grade for a student with a 52% for the first exam,63% for the second exam,and 75% for the third exam.

A)45.75%
B)65.05%
C)55.25%
D)36.35%
E)63.00%

Question 36

A disadvantage of using grouping (a frequency table)with sample data is that

A)calculations involving central tendency and variation are more complicated than central tendency and variation calculations based on ungrouped data.
B)the descriptive statistics are less precise than the descriptive statistics obtained using ungrouped data.
C)the interpretation of the grouped data descriptive statistics is meaningless.
D)it is much more difficult to summarize the information than it is with the ungrouped data.
E)it is more difficult to interpret a pie chart.

Question 37

A plot of the values of a dependent variable y versus the values of an independent variable x is a _____ plot.

A)runs
B)scatter
C)dot
D)time series
E)box

Question 38

An airline company is,on average,late 10 minutes for arrivals.If the variance for the lateness statistic is 9,then the coefficient of variation is _____.

A)3
B)300
C)10
D)90
E)30

Question 39

A measurement that is separated from most of the other measurements is a(n)_____.

A)absolute extreme
B)outlier
C)mode
D)quartile
E)median

Question 40

In a given data set,the 25^th percentile is _______________ equal to the lower hinge.

A)always
B)sometimes
C)never

Question 41

A quantity that measures the variation of a population or a sample relative to its mean is called the ____.

A)range
B)standard deviation
C)coefficient of variation
D)variance
E)interquartile range

Question 42

When developing a frequency distribution,the class intervals should be ___________.

A)large.
B)small.
C)different lengths.
D)mutually exclusive.
E)of equal length.

Question 43

If there are 62 values in a data set,how many classes should be created for a frequency histogram?

A)4
B)5
C)6
D)7
E)8

Question 44

A local airport keeps track of the percentage of flights arriving within 15 minutes of their scheduled arrivals. The stem-and-leaf plot of the data for one year is below. The leaf unit is 0.1.
$$\begin{array} { l l } 76 & 9 \\77 & 114 \\78 & \\79 & 07 \\80 & 88 \\81 & 2 \\82 & 1 \\83 & 88\end{array}$$

-In developing a histogram of these data,how many classes would be used?

A)4
B)5
C)6
D)7
E)8

Question 45

What would be the class length that would be used in creating a frequency histogram?

A)1.4
B)8.3
C)1.2
D)1.7
E)0.9

Question 46

A company collected the ages from a random sample of its middle managers with the resulting frequency distribution shown below:
$$\begin{array} { l r } \text { Class Interval } & \text { Frequency } \\20 \text { to } < 25 & 8 \\25 \text { to } < 30 & 6 \\30 \text { to } < 35 & 5 \\35 \text { to } < 40 & 12 \\40 \text { to } < 45 & 15 \\45 \text { to } < 50 & 7\end{array}$$

-What is the midpoint of the third class interval?

A)22.5
B)27.5
C)32.5
D)37.5
E)42.5

Question 47

A company collected the ages from a random sample of its middle managers with the resulting frequency distribution shown below:
$$\begin{array} { l r } \text { Class Interval } & \text { Frequency } \\20 \text { to } < 25 & 8 \\25 \text { to } < 30 & 6 \\30 \text { to } < 35 & 5 \\35 \text { to } < 40 & 12 \\40 \text { to } < 45 & 15 \\45 \text { to } < 50 & 7\end{array}$$

-What would be the approximate shape of the relative frequency histogram?

A)Uniform
B)Normal
C)Bimodal
D)Skewed to the left
E)Skewed to the right

Question 48

What would be the first class interval for the frequency histogram?

A)5.2 - 6.5
B)5.2 - 6.0
C)5.0 - 6.0
D)5.2 - 6.6
E)5.2 - 6.4

Question 49

What is the approximate shape of the distribution of the data?

A)Normal
B)Skewed to the right
C)Skewed to the left
D)Bimodal
E)Uniform

Question 50

A local airport keeps track of the percentage of flights arriving within 15 minutes of their scheduled arrivals. The stem-and-leaf plot of the data for one year is below. The leaf unit is 0.1.
$$\begin{array} { l l } 76 & 9 \\77 & 114 \\78 & \\79 & 07 \\80 & 88 \\81 & 2 \\82 & 1 \\83 & 88\end{array}$$

-What would be the class length for creating the frequency histogram?

A)1.4
B)0.8
C)2.7
D)1.7
E)2.3

Question 51

If there are 130 values in a data set,how many classes should be created for a frequency histogram?

A)4
B)5
C)6
D)7
E)8

Question 52

If there are 120 values in a data set,how many classes should be created for a frequency histogram?

A)4
B)5
C)6
D)7
E)8

Question 53

A company collected the ages from a random sample of its middle managers with the resulting frequency distribution shown below:
$$\begin{array} { l r } \text { Class Interval } & \text { Frequency } \\20 \text { to } < 25 & 8 \\25 \text { to } < 30 & 6 \\30 \text { to } < 35 & 5 \\35 \text { to } < 40 & 12 \\40 \text { to } < 45 & 15 \\45 \text { to } < 50 & 7\end{array}$$

-What is the relative frequency for the largest interval?

A)0.132
B)0.226
C)0.231
D)0.283
E)0.288

Question 54

What is the smallest percent spent on computing?

A)5.9
B)5.6
C)5.2
D)5.02
E)50.2

Question 55

For a bell-shaped distribution,score x would be considered an outlier if:

A)x = 15,mean = 20,standard deviation = 3
B)x = 15,mean = 50,standard deviation = 30
C)x = 15,mean = 25,standard deviation = 5
D)x = 15,mean = 10,standard deviation = 100
E)x = 15,mean = 50,standard deviation = 10

Question 56

If there are 30 values in a data set,how many classes should be created for a frequency histogram?

A)4
B)5
C)6
D)7
E)8

Question 57

Which of the following graphical tools is not used to study the shapes of distributions?

A)Stem-and-leaf display
B)Scatter plot
C)Histogram
D)Dot plot
E)Cumulative frequency distribution

Question 58

If a frequency histogram were to be created using these data,how many classes would you create?

A)4
B)5
C)6
D)7
E)8

Question 59

Which of the following sample statistics is a measure of variation that is based only on the minimum and maximum values in a sample?

A)Range
B)Standard deviation
C)Variance
D)Interquartile range
E)Coefficient of variation

Question 60

A local airport keeps track of the percentage of flights arriving within 15 minutes of their scheduled arrivals. The stem-and-leaf plot of the data for one year is below. The leaf unit is 0.1.
$$\begin{array} { l l } 76 & 9 \\77 & 114 \\78 & \\79 & 07 \\80 & 88 \\81 & 2 \\82 & 1 \\83 & 88\end{array}$$

-What is the sample size?

A)7
B)9
C)10
D)11
E)12

Question 61

What is the median?

A)0.709
B)0.710
C)0.920
D)0.725
E)0.550

Question 62

What is the mean?

A)0.709
B)0.710
C)0.920
D)0.725
E)0.550

Question 63

What is the mode?

A)3
B)5
C)2
D)4
E)3.25

Question 64

What is the median?

A)8.0
B)7.0
C)6.0
D)9.0
E)7.4

Question 65

What is the mean?

A)3447
B)3213
C)3250
D)6120
E)3445

Question 66

What is the mode?

A)71.5
B)72.0
C)77.0
D)71.0
E)73.0

Question 67

What is the mean?

A)3
B)5
C)2
D)4
E)3.25

Question 68

What is the median?

A)8
B)23.5
C)16
D)17
E)18

Question 69

What is the mean?

A)71.5
B)72.0
C)77.0
D)71.0
E)73.0

Question 70

What is the median?

A)70
B)75
C)68
D)71
E)80

Question 71

What is the mean?

A)8
B)23.5
C)16
D)17
E)18

Question 72

What is the median?

A)71.5
B)72.0
C)77.0
D)71.0
E)73.0

Question 73

What is the median?

A)3447
B)3213
C)3250
D)6120
E)3445

Question 74

What is the mean?

A)8.0
B)7.0
C)6.0
D)9.0
E)7.4

Question 75

What is the median?

A)3
B)5
C)2
D)4
E)3.25

Question 76

What is the mode?

A)0.709
B)0.710
C)0.920
D)0.725
E)0.550

Question 77

What is the mode?

A)8.0
B)7.0
C)6.0
D)9.0
E)7.4

Question 78

What is the mode?

A)70
B)75
C)68
D)71
E)80

Question 79

What is the mode?

A)8
B)23.5
C)16
D)17
E)18

Question 80

What is the mean?

A)70
B)75
C)68
D)71
E)80