AnswersMathematics IIIStatistics and Probability

Statistics and Probability — Test Answers

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The table shows the ages of houses to the nearest year in a neighborhood. Using the age of the houses as the random variable, cap x , which graph shows the probability distribution, cap p sub cap x times x , of a randomly chosen house?

A
Image with description The bar graph is titled Probability Distribution. The horizontal axis lists 0 to 4 in increments of 1 and is labeled as x. The vertical axis lists 0 to 0 point 3 5 in increments of 0 point 0 5 and is labeled as a P subscript x of x. There are 4 bars on the graph. The first bar is at 1 and its height is 0 point 1 5, the second bar is at 2 and its height is 0 point 2, the 3rd bar is at 3 and its height is 0 point 2 5, and the 4th bar is at 4 and its height is 0 point 3.
B
Image with description The bar graph is titled Probability Distribution. The horizontal axis lists 0 to 4 in increments of 1 and is labeled as x. The vertical axis lists 0 to 0 point 3 5 in increments of 0 point 0 5 and is labeled as a P subscript x of x. There are 4 bars on the graph. The first bar is at 1 and its height is 0 point 1 6, the second bar is at 2 and its height is 0 point 2 2, the 3rd bar is at 3 and its height is 0 point 2 8, and the 4th bar is at 4 and its height is 0 point 3 3.
C
Image with description The bar graph is titled Probability Distribution. The horizontal axis lists 0 to 4 in increments of 1 and is labeled as x. The vertical axis lists 0 to 0 point 1 4 in increments of 0 point 0 2 and is labeled as a P subscript x of x. There are 4 bars on the graph. The first bar is at 1 and its height is 0 point 6 5, the second bar is at 2 and its height is 0 point 1, the 3rd bar is at 3 and its height is 0 point 1 2, and the 4th bar is at 4 and its height is 0 point 1 3.
D
Image with description The bar graph is titled Probability Distribution. The horizontal axis lists 0 to 4 in increments of 1 and is labeled as x. The vertical axis lists 0 to 0 point 4 5 in increments of 0 point 0 5 and is labeled as a P subscript x of x. There are 4 bars on the graph. The first bar is at 1 and its height is 0 point 1, the second bar is at 2 and its height is 0 point 2, the 3rd bar is at 3 and its height is 0 point 3, and the 4th bar is at 4 and its height is 0 point 4.
3

How do the mean and median change from plot 1 to plot 2?

A
The mean remains the same, and the median decreases.
B
The mean decreases, and the median remains the same.
C
The mean and median decrease.
D
The mean and median remain the same.
4

How could the graph be redrawn so that the difference in monthly electric cost does not appear as great?

A
The interval on the y -axis could be changed to count by 1 s.
B
The scale on the y -axis could be changed to 0 - 150 .
C
The interval on the y -axis could be changed to count by 20 s.
D
The scale on the y -axis could be changed to 100 - 120 .
5

Each person takes turns rolling two dice. If the sum is odd, the person playing odds gets points equal to the sum of the roll. If the sum is even, the person playing evens gets points equal to the sum of the roll. Note that the points earned is independent of who is rolling the dice. If Jessica is challenged to a game of Sums, which statement is accurate in every aspect in guiding her to the correct choice of choosing to play odds or evens?

A
cap e times evens will be more because there are more even numbers that result from rolling two dice. Therefore, Jessica should play evens.
B
cap e times evens will be more because the value of the even numbers on the dice are more. Therefore, Jessica should play evens.
C
cap e times evens is equal to cap e times odds because the different probabilities and values end up balancing out, creating a fair game. Therefore, Jessica may choose whichever she likes.
D
cap e times odds will be more because the probability for each odd number being rolled is greater. Therefore, Jessica should play odds.
6

Which statement is true about the data set?

A
The value of the first quartile is 13.
B
It has a range of 52 pages.
C
The data is symmetric.
D
Its median is greater than its mode.
11

Glenda checks the computer monitors made at her company for defects. It has been shown that 0 point 5 percent of the monitors are defective. She decides to check several monitors and record if they are defective. Which of the following will make this process into a binomial experiment?

A
Glenda chooses to check 300 monitors.
B
Glenda checks 300 monitors and records the number that are defective until she gets greater than 0 point 5 percent defective monitors.
C
Glenda checks the monitors until she has 300 non-defective monitors.
D
Glenda checks the monitors until she has 300 defective monitors.
19

The mean test scores with standard deviations of four English classes are given. Class Mean Standard Deviation Mrs. Jones 89 1 point 9 Mrs. Rijo 82 1 point 4 Mr. Phan 73 3 point 4 Mrs. Scott 90 6 point 1 Which statement is most likely to be true?

A
The scores of Mrs. Scott’s class are the closest to the class mean.
B
The scores of Mr. Phan’s class are the closest to the class mean.
C
The scores of Mrs. Jones’s class are the closest to the class mean.
D
The scores of Mrs. Rijo’s class are the closest to the class mean.
20

A convenience sample differs from a voluntary sample in that

A
convenience samples survey each participant once, and voluntary samples survey each participant numerous times.
B
convenience sampling is not a probability-based method, and voluntary sampling is.
C
a convenience sample is structured based on accessibility to the researcher, and a voluntary sample is based on participant interest.
D
convenience sampling is a method of random sampling, and a voluntary sample is not.

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