Question 1

Measures like the average (mean) or median of a group are called
A) measures of central tendency.
B) experimental statistics.
C) demonstrative statistics.
D) inferential statistics.

Accepted Answer

Measures of central tendency, such as the mean or median, describe the central position within a distribution of data. These measures are fundamental in statistical analysis to summarize a data set with a single value that represents the middle or center of its distribution.

Question 2

A difference in two numbers, like the means of two groups, is statistically significant when
A) it is smaller than usual.
B) it is particularly likely to occur.
C) it is unlikely to occur by chance.
D) its probability is near .50.

Accepted Answer

Statistical significance is determined when a difference (such as between the means of two groups) is unlikely to occur by chance, indicating that the observed difference is likely due to a specific cause or effect rather than random variation.

Question 3

Most people assess the risk of elective surgery (e.g., a "nose job") as being safer than nonelective surgery. This example demonstrates which concept about how perceptions influence probabilities?
A) bias toward control of events
B) bias toward known events
C) regression toward the mean
D) base rate neglect

Accepted Answer

This example illustrates the bias toward control of events, where people tend to believe that outcomes are more favorable when they have control over the situation, such as choosing to undergo elective surgery, compared to situations that are not under their control, like nonelective surgeries.

Question 4

Carlos was timing how fast his rat ran the maze. He found that rat A ran extraordinarily fast yesterday compared to the five other rats in his sample. According to the concept regression toward the mean, which of following is likely to happen tomorrow?
A) Rat A will run extraordinarily fast
B) Rat A will run at a pace more similar to the average running pace
C) Rat A will run the slowest of the sample of rats
D) Rat A will refuse to run

Accepted Answer

The concept of regression toward the mean suggests that if an extreme score or performance is observed, the next observation will likely be closer to the average. Therefore, Rat A is likely to run at a pace more similar to the average running pace of the group on the following day.

Question 5

Discuss the nature of the laws of chance and the long run.

Accepted Answer

The answer of Discuss the nature of the laws of...

Question 6

Draw a tree diagram representing the possible outcomes of 4 flips of a fair coin. Why would you be likely to be correct if you guessed a pattern of "50% heads, 50% tails"?

Accepted Answer

The answer of Draw a tree diagram representing the possible...

Question 7

Explain the conjunction error, including an example of research investigating the conjunction error.

Accepted Answer

The answer of Explain the conjunction error, including an example...

Question 8

Julie is single woman living in southern California. She is an independent thinker and plays the piano. She regularly donates money to her local animal shelter. If I think that it is more likely that Julie has pets and is a bank teller than it is that she is just a bank teller, I am making a/an
A) heuristic error.
B) conjunctive error.
C) illusory correlation.
D) gambler's fallacy.
E) None of the above

Accepted Answer

This is an example of a conjunctive error, where the probability of two events happening together (being a bank teller and having pets) is incorrectly judged to be more likely than just one of those events happening on its own (being a bank teller).

Question 9

Personal estimates of the probability of uncertain events are called __________; mathematically determined statements about the likelihood of events with known frequencies are called __________.
A) mutual outcomes…..joint outcomes
B) conditional outcomes…..joint outcomes
C) subjective probabilities…..objective probabilities
D) objective probabilities…..subjective probabilities
E) None of the above

Accepted Answer

Personal estimates of the probability of uncertain events are referred to as subjective probabilities because they are based on personal judgment or opinion rather than on precise measurement or calculation. Mathematically determined statements about the likelihood of events with known frequencies are called objective probabilities, as they are based on factual data and statistical analysis.

Question 10

The probability of an event occurring over many trials is called its __________.
A) total rate.
B) conditional probability.
C) cumulative probability.
D) uncertainty.

Accepted Answer

Cumulative probability refers to the probability of an event occurring over a series of trials or over time, accumulating the probabilities from multiple instances.

Question 11

Anyone can figure out the number or percentage of trials on which a particular outcome will occur, because of
A) the rules of logic.
B) the use of circle diagrams.
C) the laws of chance.
D) psychic abilities.

Accepted Answer

The laws of chance, or probability theory, allow for the calculation of the likelihood of various outcomes in trials or experiments.

Question 12

Probabilities near a value of __________ represent maximum uncertainty.
A) 1
B) 25% or 75%
C) 0.5
D) 0 (zero)

Accepted Answer

Probabilities near a value of 0.5 (or 50%) represent maximum uncertainty because this value indicates that an event is just as likely to happen as not happen, embodying a state of complete indecision or maximum uncertainty.

Question 13

The probability of getting "heads" three times in a row in three flips of a fair coin is
A) 0.5
B) 0.25
C) 0.125
D) 0.0625

Accepted Answer

The probability of getting heads in one flip is 0.5. For three independent flips, the probabilities multiply: 0.5 * 0.5 * 0.5 = 0.125.

Question 14

John and Lisa have had 5 children, all girls! Given equal likelihood of a healthy pregnancy at each conception, what is the probability of having 5 female babies in a row?
A) 0.03125
B) 0.00001
C) 0.125
D) 0.00145

Accepted Answer

The probability of having a girl is 0.5 (assuming equal likelihood of having a boy or a girl). For 5 girls in a row, it's $0.5^5 = 0.03125$.

Question 15

Probabilities based on brief or short "runs" are similar to research results based on
A) small samples.
B) biased samples.
C) nonrepresentative samples.
D) All of the above

Accepted Answer

Probabilities based on short runs or small samples can be misleading because they may not accurately represent the larger population or the true probabilities, similar to the issues with biased or nonrepresentative samples.

Question 16

The probability of two independent events occurring together is __________ __________ __________ the probability of one of those events occurring alone.
A) more likely than
B) less likely than
C) equally likely as
D) completely unrelated to
E) None of the above

Accepted Answer

The probability of two independent events occurring together is the product of their individual probabilities, which is always less than or equal to the probability of either event occurring alone.

Question 17

What is the probability of getting a 4 or a 6 on one roll of a single die?
A) about 3%
B) about 20%
C) about 35%
D) about 50%

Accepted Answer

There are 6 possible outcomes when rolling a die: 1, 2, 3, 4, 5, or 6. Two of these outcomes are 4 or 6, so the probability of getting a 4 or a 6 is 2/6 = 1/3, which is about 35%.

Question 18

What is the probability of getting a 1, 2, 3, 4, 5, or 6 on one roll of a single die?
A) 0.3
B) 0.5
C) 0.75
D) 1

Accepted Answer

The probability of rolling a 1, 2, 3, 4, 5, or 6 on a single die is 1, since these are all the possible outcomes on a standard 6-sided die.

Question 19

The belief that chance processes are self-correcting is called
A) the gambler's fallacy.
B) probability ignorance.
C) overconfidence.
D) conjunction error.

Accepted Answer

The gambler's fallacy is the belief that if something happens more frequently than normal during a given period, it will happen less frequently in the future, or vice versa, under the mistaken assumption that long-term outcomes must balance.

Question 20

Rhonda is going to "33 Flavors" to get a double-scoop of ice cream. What is the probability that she will order Cherry Vanilla or Butterscotch?
A) 12086
B) 12055
C) 1 / 33 X 1 / 33
D) It is impossible to tell, Rhonda is very unpredictable

Accepted Answer

There are 33 flavors of ice cream, and Rhonda is ordering a double-scoop. So, there are 33 * 33 = 1089 possible combinations of flavors. There are 2 flavors that Rhonda is interested in, Cherry Vanilla and Butterscotch. So, there are 2 * 33 = 66 possible combinations of flavors that include either Cherry Vanilla or Butterscotch. Therefore, the probability that Rhonda will order Cherry Vanilla or Butterscotch is 66 / 1089 = 1 / 16.

Quiz 7: Likelihood and Uncertainty: Understanding Probabilities

Measures like the average (mean) or median of a group are called

A difference in two numbers, like the means of two groups, is statistically significant when

Most people assess the risk of elective surgery (e.g., a "nose job") as being safer than nonelective surgery. This example demonstrates which concept about how perceptions influence probabilities?

Carlos was timing how fast his rat ran the maze. He found that rat A ran extraordinarily fast yesterday compared to the five other rats in his sample. According to the concept regression toward the mean, which of following is likely to happen tomorrow?

Discuss the nature of the laws of chance and the long run.

Draw a tree diagram representing the possible outcomes of 4 flips of a fair coin. Why would you be likely to be correct if you guessed a pattern of "50% heads, 50% tails"?

Explain the conjunction error, including an example of research investigating the conjunction error.

Julie is single woman living in southern California. She is an independent thinker and plays the piano. She regularly donates money to her local animal shelter. If I think that it is more likely that Julie has pets and is a bank teller than it is that she is just a bank teller, I am making a/an

Personal estimates of the probability of uncertain events are called ; mathematically determined statements about the likelihood of events with known frequencies are called .

The probability of an event occurring over many trials is called its __________.

Anyone can figure out the number or percentage of trials on which a particular outcome will occur, because of

Probabilities near a value of __________ represent maximum uncertainty.

The probability of getting "heads" three times in a row in three flips of a fair coin is

John and Lisa have had 5 children, all girls! Given equal likelihood of a healthy pregnancy at each conception, what is the probability of having 5 female babies in a row?

Probabilities based on brief or short "runs" are similar to research results based on

The probability of two independent events occurring together is __ the probability of one of those events occurring alone.

What is the probability of getting a 4 or a 6 on one roll of a single die?

What is the probability of getting a 1, 2, 3, 4, 5, or 6 on one roll of a single die?

The belief that chance processes are self-correcting is called

Rhonda is going to "33 Flavors" to get a double-scoop of ice cream. What is the probability that she will order Cherry Vanilla or Butterscotch?