# Observational or experimental study?

QUESTION 1·1 POINT- Observational or experimental study

In a study on study habits, a researcher randomly selected an equal number of men and women to survey. Is the study observational or experimental? If it is an experiment, what is the controlled factor?

The study is an experiment. The controlled factor is a person’s study habits.

The study is an observational study.

The study is an experiment. The controlled factor is the survey.

The study is an experiment. The controlled factor is the category, men or women.

QUESTION 2·1 POINT

A hotel asks its patrons to add a gratuity for the housekeeping service. The options are five dollars, ten dollars, fifteen dollars, and twenty dollars. What is the level of measurement of the data?

nominal

ordinal

interval

ratio

Matthew wants to estimate the mean height of students attending his college. He records the heights of 450 randomly selected students attending the college. What is the population?

the mean height of the randomly selected students

the mean height of all students attending the college

the 450 randomly selected students

all the students attending the college

the heights of the randomly selected students

QUESTION 4·1 POINT

To study the eating habits of all athletes in his school, Christopher obtains a list of the athletes and collects data from every 10th person on the list. Which type of sampling is used?

Cluster sampling

Stratified sampling

Convenience sampling

Systematic sampling

QUESTION 5·1 POINT

In order to study the mean blood pressure of people in his town, Richard samples the population by dividing the residents by age and randomly selecting a proportionate number of residents from each age group. Which type of sampling is used?

Convenience sampling

Cluster sampling

Stratified sampling

Systematic sampling

QUESTION 6·1 POINT

A small startup company wishes to know how many hours, per week, that its employees spend commuting to and from work. The number of hours for each employee are shown below. Construct a frequency table for grouped data using four classes.

10, 4, 19, 14, 13, 21, 22, 9, 13, 10, 3, 12, 15, 20, 15, 3, 5, 22, 17, 15

 Lower Class Limit Upper Class Limit Frequency

QUESTION 7·1 POINT

The frequency table below shows the ages of the students in an astronomy class.

Complete the Relative Frequency column of the table.

 Age Frequency Relative Frequency 17 13 18 11 19 6 20 12 21 6 22 2

QUESTION 8·1 POINT

A group of students were surveyed about the number of times they went to a movie theater last year. Their responses are summarized in the relative frequency table below.

What is the missing relative frequency?

 Number of Movies Relative Frequency 0−1 0.08 2−3 0.20 4−5 0.30 6−7 □ 8−9 0.10 10 or more 0.08

QUESTION 9·1 POINT

The values and relative frequencies for a set of data are shown below.

Complete the cumulative relative frequency table.

 Data Value Relative Frequency Cumulative Relative Frequency 1 0.19 2 0.05 3 0.36 4 0.40

QUESTION 10·1 POINT

A data set is summarized in the frequency table below. Using the table, determine the number of values less than or equal to 7.

 Value Frequency 2 3 3 4 4 6 5 3 6 2 7 3 8 4 9 5 10 4 11 4 12 2

QUESTION 14·1 POINT

The following is a data set of the average weekly number of cups of coffee consumed by employees in an office. Find the mean and median and determine if the mean or median is the better measure of central tendency.

9,5,0,7,7,6,9,30,9,1,3,0,4,8,5,9

Mean = 7, Median = 6.5
The mean is the better measure of central tendency.

Mean = 7, Median = 6.5
The median is the better measure of central tendency.

Mean = 6.5, Median = 7
The mean is the better measure of central tendency.

Mean = 6.5, Median = 7
The median is the better measure of central tendency.

QUESTION 15·1 POINT

If the median of a data set is 16 and the mean is 10, which of the following is most likely?

The data are skewed to the left.

The data are skewed to the right.

The data are symmetrical.

QUESTION 17·1 POINT

The following data values represent the daily amount spent by a family during a 5 day summer vacation.

Find the standard deviation of this dataset:

\$120, \$60, \$250, \$120, \$200

• Round the final answer to one decimal place.

QUESTION 20·1 POINT

The five-number summary for a set of data is given below.

 Min Q1 Median Q3 Max 40 69 72 79 86

Using the interquartile range, which of the following are outliers? Select all correct answers.

Select all that apply:

43

44

48

64

70

QUESTION 22·1 POINT

A deck of cards contains red cards numbered 1,2,3 and blue cards numbered 1,2,3,4,5,6. Let R be the event of drawing a red card, B be the event of drawing a blue card, E be the event of drawing an even-numbered card, and O be the event of drawing an odd card.

Drawing the blue 1 is an example of which of the following events? Select all correct answers.

Select all that apply:

O′

B OR E

R OR E

R′

R AND E

R OR O

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QUESTION 23·1 POINT

A deck of cards contains red cards numbered 1,2,3,4, blue cards numbered 1,2,3,4,5,6 and green cards numbered 1,2,3,4,5,6,7,8,9. If a single card is picked at random, what is the probability that the card is blue?