Q: If two events are independent, what is the probability of both occurring?

$$P(A \cap B) = P(A) \times P(B)$$

Question 1

Which of the following is NOT a function of statistics?

Accepted Answer

Statistics involves collecting only qualitative data.

Question 2

A survey of 500 college students in a city found that 12% had been victims of violent crimes. Is the underlined value a parameter or a statistic?

Accepted Answer

Statistic

Question 3

Classify the following variable as qualitative or quantitative: The number of goals scored in a hockey game.

Accepted Answer

Quantitative

Question 4

Determine the level of measurement for the following variable: The medal received (gold, silver, bronze) by an Olympic athlete.

Accepted Answer

Nominal

Question 5

Every 10th adult entering an airport is checked for extra security screening. What sampling technique is used?

Accepted Answer

Systematic

Question 6

A travel industry researcher interviews all of the passengers on five randomly selected cruises. What sampling technique is used?

Accepted Answer

Cluster

Question 7

A lobbyist assigns a number to each senator and then uses a computer to randomly generate numbers. The lobbyist contacts the senators corresponding to these numbers. What sampling technique is used?

Accepted Answer

Simple random

Question 8

A researcher at a magazine randomly selects and interviews fifty male and fifty female artists. What sampling technique is used?

Accepted Answer

Stratified

Question 9

A company mails questionnaires to 1000 households and receives 140 responses. What type of bias is most likely present?

Accepted Answer

Nonresponse bias

Question 10

Given the following class limits: 67-74, 75-82, 83-90, 91-98, 99-106, what is the class width?

Accepted Answer

$$7$$

Question 11

What is the main difference between a bar chart and a histogram?

Accepted Answer

The bars in a bar chart are all the same width while the bars of a histogram may be of various widths.

Question 12

If the range of car sales has doubled, but the area has been multiplied by 8, what has happened to the spread of the data?

Accepted Answer

The spread has increased by a factor of 8.

Question 13

Given the data set: 10, 10, 12, 18, 12, 17, 14, what is the range?

Accepted Answer

$$18 - 10 = 8$$

Question 14

A student scores 62 on a geography test (mean = 50, standard deviation = 5) and 285 on a mathematics test (mean = 250, standard deviation = 10). What is the student's z-score for the geography test?

Accepted Answer

$$z = \frac{62-50}{5} = 2.4$$

Question 15

If you roll two dice, what is the probability that the sum is 6?

Accepted Answer

$$\frac{5}{36}$$

Question 16

If two events are independent, what is the probability of both occurring?

Accepted Answer

$$P(A \cap B) = P(A) 	imes P(B)$$

Question 17

A coin is flipped five times. What is the probability of getting at least one head?

Accepted Answer

$$1 - (\frac{1}{2})^5$ = 0.96875$$

Question 18

A human gene passes a certain disease from mother to child with a probability of 0.2 per child. If a woman has three children, what is the probability that at least one child inherits the disease?

Accepted Answer

$$1 - (0.8)^3$ = 0.488$$

Introductory Statistics Study Guide: Step-by-Step Guidance

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