Statistics 1

The process of using sample statistics to draw conclusions about true population parameters is called

Question 3 answers

statistical inference.

the scientific method.

sampling.

descriptive statistics.

Question 4

Researchers suspect that the average number of units earned per semester by college students is rising. A researcher at Calendula College wishes to estimate the number of units earned by students during the spring semester at Calendula. To do so, he randomly selects 100 student transcripts and records the number of units each student earned in the spring term. He found that the average number of semester units completed was 12.96 units per student. Identify the population of interest to the researcher.

Question 4 answers

All Calendula College students.

All college students.

All Calendula College students enrolled in the spring

All college students enrolled in the spring.

Question 5

A statistics student found a reference in the campus library that contained the median family incomes for all 50 states. She would report her data as being collected using

Question 5 answers

a designed experiment.

observational data.

a random sample.

a published source.

Question 6

Which of the following is most likely a parameter as opposed to a statistic?

Question 6 answers

The average score of the first five students completing an assignment.

The proportion of females registered to vote in a county.

The average height of people randomly selected from a database.

The proportion of trucks stopped yesterday that were cited for bad brakes.

Question 7

The universe or "totality of items or things" under consideration is called

Question 7 answers

a sample.

a population.

a parameter.

a statistic.

Question 8

The chancellor of a major university was concerned about alcohol abuse on her campus and wanted to find out the proportion of students at her university who visited campus bars on the weekend before the final exam week. Her advisor took a random sample of 250 students. The portion of students in the sample who visited campus bars on the weekend before the final exam week is an example of __________.

Question 8 answers

a categorical random variable.

a discrete random variable.

a parameter.

a statistic

Question 9 text

The following are the durations in minutes of a sample of long-distance phone calls made within the continental United States reported by one long-distance carrier.

Table 2-5

RelativeTime (in Minutes) Frequency

0 but less than 5 0.37

5 but less than 10 0.22

10 but less than 15 0.15

15 but less than 20 0.10

20 but less than 25 0.07

25 but less than 30 0.07

30 or more 0.02

Referring to Table 2-5, what is the width of each class?

Question 9 answers

1 minute

5 minutes

2%

100%

Question 10

The following are the durations in minutes of a sample of long-distance phone calls made within the continental United States reported by one long-distance carrier.

Table 2-5

RelativeTime (in Minutes) Frequency

0 but less than 5 0.37

5 but less than 10 0.22

10 but less than 15 0.15

15 but less than 20 0.10

20 but less than 25 0.07

25 but less than 30 0.07

30 or more 0.02

Referring to Table 2-5, what is the cumulative relative frequency for the percentage of calls that lasted under 20 minutes?

Question 10 answers

0.10

0.59

0.76

0.84

Question 11

The width of each bar in a histogram corresponds to the

Question 11 answers

the x-values that the bar represents.

number of observations for the x-values.

midpoint of each class.

percentage of observations in each class.

Question 12 text

In a contingency table, the number of rows and columns

Question 12 answers

must always be the same.

must always be 2.

must add to 100%.

None of the above.

Question 13 text

A sample of 200 students at a Big-Ten university was taken after the midterm to ask them whether they went bar hopping the weekend before the midterm or spent the weekend studying, and whether they did well or poorly on the midterm. The following table contains the result.

Table 2-6

Did Well in Midterm Did Poorly in Midterm

Studying for Exam 80 20

Went Bar Hopping 30 70

Referring to Table 2-6, _______ percent of the students in the sample spent the weekend studying and did well on the midterm.

Question 13 answers

40

50

72.72

80

Question 14

At a meeting of information systems officers for regional offices of a national company, a survey was taken to determine the number of employees the officers supervise in the operation of their departments, where X is the number of employees overseen by each information systems officer.

Table 2-2

X f

1 7

2 5

3 11

4 8

5 9

Referring to Table 2-2, across all of the regional offices, how many total employees were supervised by those surveyed?

Question 14 answers

15

40

127

200

Question 15

A common misuse of graphs is:

Question 15 answers

have no zero point on the vertical axis.

have equally spaced intervals on the horizontal axis.

clearly label the axes.

show proportions using percentages.

Question 16

When analyzing a single numerical variable, you may use:

Question 16 answers

a histogram

relative frequency polygon

cumulative percentage polygon

All of the above

Question 17

According to the Chebyshev rule, at least what percentage of the observations in any data set are contained within a distance of 2 standard deviations around the mean?

Question 17 answers

67%

75%

88.89%

95%

Question 18

Health care issues are receiving much attention in both academic and political arenas. A sociologist recently conducted a survey of citizens over 60 years of age whose net worth is too high to qualify for Medicaid and have no private health insurance. The ages of 25 uninsured senior citizens were as follows:

60 61 62 63 64 65 66 68 68 69 70 73 73 74 75 76 76 81 81 82 86 87 89 90 92

Calculate the coefficient of variation of the ages of the uninsured senior citizens.

Question 18 answers

13.16%

14%

15%

11.5%

Question 19

Which measure of central tendency represents a count of the most frequent value?

Question 19 answers

Arithmetic mean.

Median.

Mode.

Geometric mean.

Question 20

Health care issues are receiving much attention in both academic and political arenas. A sociologist recently conducted a survey of citizens over 60 years of age whose net worth is too high to qualify for Medicaid and have no private health insurance. The ages of 25 uninsured senior citizens were as follows:

60 61 62 63 64 65 66 68 68 69 70 73 73 74 75 76 76 81 81 82 86 87 89 90 92

Identify which of the following is the correct statement.

Question 20 answers

One fourth of the senior citizens sampled are below 65.5 years of age.

The middle 50% of the senior citizens sampled are between 65.5 and 73.0 years of age.

The average age of senior citizens sampled is 73.5 years of age.

All of the above are correct.

Question 21

Which of the following is NOT a measure of central tendency?

Question 21 answers

The arithmetic mean.

The geometric mean.

The mode.

The interquartile range.

Question 22

1.According to the empirical rule, if the data form a bell-shaped distribution, then about _____ percent of the observations will be within plus or minus 3 standard deviations from the mean.

Question 22 answers

68

97.5

95

99.7

Question 23

When extreme values are present in a set of data, which of the following descriptive summary measures are most appropriate:

Question 23 answers

CV and range.

arithmetic mean and standard deviation.

interquartile range and median.

variance and interquartile range.

Question 24

Health care issues are receiving much attention in both academic and political arenas. A sociologist recently conducted a survey of citizens over 60 years of age whose net worth is too high to qualify for Medicaid and have no private health insurance. The ages of 25 uninsured senior citizens were as follows:

60 61 62 63 64 65 66 68 68 69 70 73 73 74 75 76 76 81 81 82 86 87 89 90 92

Identify the third quartile of the ages of the uninsured senior citizens.

Question 24 answers

71.5 years

81.5 years

55.5 years

45.5 years

Question 25

Health care issues are receiving much attention in both academic and political arenas. A sociologist recently conducted a survey of citizens over 60 years of age whose net worth is too high to qualify for Medicaid and have no private health insurance. The ages of 25 uninsured senior citizens were as follows:

60 61 62 63 64 65 66 68 68 69 70 73 73 74 75 76 76 81 81 82 86 87 89 90 92

Identify which of the following is the correct statement.

Question 25 answers

One fourth of the senior citizens sampled are below 64 years of age.

The middle 50% of the senior citizens sampled are between 65.5 and 73.0 years of age.

One quarter of the senior citizens sampled are older than 81.5 years of age.

All of the above are correct.