# CLAST Math On-Line Practice Quiz

### CLAST Statistics Skills Including Probability

Identify information contained in graphs Determine the mean, median, and mode Use the fundamental counting principle Recognize properties and interrelationships among the mean, median, and mode Choose the most appropriate procedures for selecting an unbiased sample Identify the probability of a specified outcome Infer relations and make accurate predictions from studying statistical data Interpret real-world data involving frequency and cumulative frequency tables Solve real-world problems involving probabilities

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## Question 1

A college president wants to find out which courses are popular with students. The president decides to conduct a survey of a sample of students. What procedure would be most appropriate for obtaining a statistically unbiased sample of the college's students?

a) Survey a random sample of students from the English department.
b) Survey the first hundred students from an alphabetical listing.
c) Survey a random sample of students from a list of the entire student body.
d) Have students voluntarily mail in their preferences.

## Question 2

A city's elementary school board needs to estimate the average number of school-age children per house in its city. To do so, the board decides to conduct a survey. What procedure would be most appropriate for selecting a statistically unbiased sample?

a) Randomly select geographic regions of the city and then survey a random sample of people within the regions.
b) Survey a random sample of the people who work at a local medical center.
c) Select the largest grocery store in the city and survey a random sample of its customers.
d) Survey all the residents of the largest subdivisions in the city.

## Question 3

The graph below represents the monthly average temperature for 7 months of the year. How much higher is the average temperature in August than it is in June?

a) 10º
b) 15º
c) 20º
d) 12º

## Question 4

The graph below represents the yearly rainfall in inches in Sagamore County for 1985-1990. Find the rainfall for 1987.

a) 34 inches
b) 22 inches
c) 38 inches
d) 26 inches

## Question 5

The number of hours required in each discipline of a college core curriculum is represented by the circle graph below. What percent of these hours is in art and English combined?

a) 48.9%
b) 51.2%
c) 42.6%
d) 53.2%

## Question 6

The graph below depicts the size (square feet) and sales price (\$) for homes sold in New York (o) and homes sold in Arizona (x) as determined by the 1990 Real Estate Association survey. Which of the following is true based on the graph below?

a) A relationship between price and size exists ONLY for homes in New York.
b) Larger homes tend to cost more than smaller homes; a stronger relationship exists for homes in Arizona than for homes in New York.
c) Larger homes tend to cost more than smaller homes; a stronger relationship exists for homes in New York than for homes in Arizona.
d) A relationship between price and size exists ONLY for homes in Arizona.

## Question 7

What is the mode in the following sample?

1, 9, 23, 23, 23, 2, 20, 23

a) 15.5
b) 23
c) 21.5
d) 12

## Question 8

What is the mean in the following sample?

1, 2, 7, 2, 10, 6, 2, 2, 28, 20

a) 4
b) 8
c) 14.5
d) 2

## Question 9

What is the median in the following sample?

3, 7, 15, 20, 3, 20, 1, 19, 20

a) 10.5
b) 15
c) 20
d) 12

## Question 10

The number of patients treated at Dr. Jason's dentist office each day was recorded for 11 days. Using the given data, find the mean, the median, and the mode for this sample.

3, 17, 20, 11, 23, 12, 16, 1, 23, 23, 5

a) 14, 16, 23
b) 23, 16, 14
c) 14, 23, 16
d) 12, 23, 16

## Question 11

In a mathematics class, half the students scored 23 on an achievement test. Most of the remaining students scored 38 except for a few students who scored 78. Which of the following statements is true about the distribution of the scores?

a) The median is less than the mode.
b) The mean and the median are the same.
c) The mean is less than the mode.
d) The mean is greater than the median.

## Question 12

The graph below represents the distribution of scores on a placement test for students at Central High School. Select the statement that is true about the distribution of scores.

a) The mean is less than the mode.
b) The median and the mode are the same.
c) The mean and the mode are the same.
d) The median is greater than the mode.

## Question 13

The table below shows the distribution of families by income in Chicago, Illinois.

 Income Level Percent of Families \$ 0 - 9, 999 3 10, 000 - 14, 999 7 15, 000 - 19, 999 21 20, 000 - 24, 999 43 25, 000 - 34, 999 10 35, 000 - 49, 999 8 50, 000 - 79, 999 4 80, 000 - 119, 000 3 120, 000 and over 1

Identify the amount below which 74 percent of the families in Chicago have lower incomes.

a) \$15, 000
b) \$25, 000
c) \$35, 000
d) \$20, 000

## Question 14

From a group of six boys and five girls, a boy and a girl will be selected to attend a conference. How many different pairs can be chosen?

a) 60
b) 15
c) 45
d) 30

## Question 15

A panel of judges is to consist of 2 women and 3 men. A list of potential judges has 4 women and 6 men on it. How many different panels could be created from this list?

a) 30
b) 6
c) 20
d) 120

## Question 16

The probability of getting an A in Mrs. Ford's class in any semester is 27%. What is the probability of NOT getting an A?

a) 108%
b) 46%
c) 73%
d) 63%

## Question 17

A box contains seven red, six white, and two blue balls. Two balls are drawn from the box at random without replacement. What is the probability that neither ball is red?

a) 8/15 x 8/15
b) 8/15 x 7/14
c) 8/15 x 6/15
d) 8/15 x 9/14

## Question 18

Two representatives are chosen at random from a group of 60 students that has 30 girls and 30 boys. What is the probability that the representatives selected are either both boys or both girls?

a) 2/30 + 2/30
b) 2/30 x 2/30
c) 30/60 x 29/59
d) 2 x 30/60 x 29/59

## Question 19

Research shows that in the U.S., 52% of adults aged 18-21 work full time, 48% are students, and 15% both work full time and are students. If you choose a person from this age group at random, what is the probability that the person works full time, is a student, or both?

a) 85%
b) 63%
c) 100%
d) 15%

## Question 20

The following is a description of students at a high school by sex and student classification.

 Freshmen Sophomore Junior Senior Male 12% 15% 11% 8% Female 20% 13% 11% 10%

Find the probability that a randomly selected high school student is male.

a) 0.46
b) 0.32
c) 0.54
d) 0.18

## Question 21

The following is a distribution of the cause of fires nationally:

 Cause Percent of all Fires Cooking 35 Smoking 15 Appliances 18 Heating system 9 Electrical system 8 Other 15

If it is known that a fire has NOT been caused by the heating or electrical systems, find the probability that it was caused by cooking.

a) 9/50
b) 18/83
c) 7/20
d) 35/83

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