AnswersConcepts in Probability and Statistics - MA3120 B-CRCumulative Exam

Cumulative Exam — Cumulative exam Answers

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21
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What does a residual value of 1.3 mean when referring to the line of best fit of a data set?

A
A data point is 1.3 units above the line of best fit.
B
A data point is 1.3 units below the line of best fit.
C
The line of best fit has a slope of –1.3
D
The line of best fit has a slope of 1.3.
22
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David is a statistician. He has a sample size of 40 (which he cannot change). What element of his hypothesis test can he adjust to minimize the probability that he incorrectly rejects the null hypothesis?

A
the mean of the population
B
the mean of the sample
C
the standard deviation of the population
D
the significance level of the test
23

The two-way table represents data from a survey asking students whether they plan to attend college, travel, or both after high school. Which is the marginal relative frequency for students who plan to attend college? Round the answer to the nearest percent.

Question illustration
A
18%
B
22%
C
35%
D
82%
24

Tiana compares the length of a name on a nameplate to the number of letters in the name. She draws the scatterplot below, and then she plots and determines an equation for the trend line. NameplatesBased on the information above, which is the best estimate of the number of letters that a name contains if the nameplate is 6 inches long?

Question illustration
A
3
B
4
C
10
D
12
25

Which table shows no correlation?

A
A 2-row table with 7 columns. The first row is labeled x with entries 3, 5, 6, 8, 10, 14, 15. The second row is labeled y with entries negative 1, negative 2, negative 3, negative 2, negative 5, negative 4, negative 8.
Option A
B
A 2-row table with 7 columns. The first row is labeled x with entries 3, 5, 6, 8, 10, 14, 15. The second row is labeled y with entries negative 6, negative 7, negative 4, negative 2, 0, negative 1, positive 3.
Option B
C
A 2-row table with 7 columns. The first row is labeled x with entries 3, 5, 6, 8, 10, 14, 15. The second row is labeled y with entries negative 2, negative 4, positive 6, positive 8, positive 12, positive 10, negative 16.
Option C
D
A 2-row table with 7 columns. The first row is labeled x with entries 3, 5, 6, 8, 10, 14, 15. The second row is labeled y with entries negative 3, negative 5, negative 9, negative 11, negative 13, negative 15, negative 17.
Option D
26

Which relationships could have a negative correlation? Select three options.

A
number of hours worked and free time
B
speed of a car and minimum stopping distance
C
the speed of a train and the length of time to reach the destination
D
adult’s head circumference and age
E
a tadpole’s age and the length of it’s tail
27

The box plots below show the ages of college students in different math courses. Math 1 Math 2Which statement is true?

Question illustration
A
The median age of the students in Math 1 is greater than the median age of the students in Math 2.
B
The median age of the students is Math 1 is less than the median age of the students in Math 2.
C
The mean and median age are most likely the same for both sets of data.
D
The mean and median age are more likely to be the same for the students in Math 1.
28

Two video games, Star Chasers and Song Hero, had the same average price over a 10-month period. During that time, the price of Song Hero showed greater variability. If Song Hero was priced between $35 and $49 during the 10-month period, which statement is most likely true about price of Star Chasers during that time?

A
The highest price and the lowest price of the game differ by more than $14.
B
The highest price and the lowest price of the game differ by less than $14.
C
The mean price was more than $42.
D
The mean price was less than $42.
29

Which of the following probabilities is the greatest for a standard normal distribution?

A
P (negative 1.5 less-than-or-equal-to z less-than-or-equal-to negative 0.5)
Option A
B
P (negative 0.5 less-than-or-equal-to z less-than-or-equal-to 0.5)
Option B
C
P (0.5 less-than-or-equal-to z less-than-or-equal-to 1.5)
Option C
D
P (1.5 less-than-or-equal-to z less-than-or-equal-to 2.5)
Option D
30

The scatterplot below shows the shoe sizes of students and the number of books the students collected for the library book drive.Which statement about the scatterplot is true?

Question illustration
A
In general, each student collected a number of books equal to his or her shoe size.
B
In general, the shoe size of a student does not affect the number of books collected.
C
As shoe size increases, the number of books collected decreases.
D
As shoe size increases, the number of books collected increases.
31

The table shows the maze-completion times, in seconds, of two sets of mice in an experiment. Which statement is true about the variability of the group times?

Question illustration
A
The times in Group A have a greater standard deviation.
B
The times in Group A have a greater median.
C
The times in Group B have a greater interquartile range.
D
The times in Group B have a greater mean.
32

The histogram below shows the number of properties in a town that sold within certain time periods. Why might the graph be considered misleading?

Question illustration
A
The scales on the x- and y-axes are unequal.
B
The interval on the x-axis is too large for the data set.
C
The scale on the y-axis misrepresents the difference in the heights of the bars.
D
The interval on the y-axis is too large for the data set.
33

The histogram shows the weights, in pounds, of checked luggage on a flight.

Question illustration
A
The mean is most likely less than 27 pounds.
B
The mean is most likely exactly 27.5 pounds.
C
The mean is most likely about 28 pounds.
D
The mean is most likely more than 28 pounds.
34

The box plots show the distributions of weights of cucumbers and zucchini collected from a garden. Which statement explains the best measure of variability to use to compare the data sets?

Question illustration
A
The mean is the best measure because the data sets have the same minimum weight.
B
The range is the best measure because the distribution of zucchini weights is skewed left.
C
The median is the best measure because the data sets have different medians.
D
The standard deviation is the best measure because both data distributions are symmetric.
35

A company sells name plates for doors. An employee takes a random sample of name plates, measures the length of each name (in inches), and counts the number of letters in each name. She generates the scatterplot and trend line equation shown below. Name PlatesA customer would like the company to build him a name plate that is 22 inches long. What is the best estimate of the number of letters the company can have on the name plate?

Question illustration
A
9
B
10
C
12
D
39
36

Saleem wants to compare the data in the four tables below. He graphs the data in each table and writes the rounded values for a, b, and r below each table, as shown.Table AMath Scores vs. Science ScoresTable BMath Scores vs. Science Scores Table CMath Scores vs. Science ScoresTable DMath Scores vs. Science ScoresWhich set of data has the weakest association with its trend line?

Question illustration
A
the data in table A
B
the data in table B
C
the data in table C
D
the data in table D
37

Maria gathered the data in the table. She finds the line of best fit to be y = 2.78x – 4.4.

Question illustration
A
–6.72
B
–0.58
C
0.58
D
6.72
38

The box plots show the average gas mileage, in miles per gallon, of the cars sold at a dealership in June and in December.Gas Mileage of Cars Sold in JuneGas Mileage of Cars Sold in DecemberWhich inference can be made about the cars?

Question illustration
A
The type of cars sold in June typically gets better gas mileage.
B
The type of cars sold in December typically gets better gas mileage.
C
The types of cars sold in the two months typically get about the same gas mileage.
D
The types of cars sold in the two months typically get better gas mileage than those sold in other months.
39

A simple random sample of 50 adults was surveyed, and it was found that the mean amount of time that they spend surfing the Internet per day is 54.2 minutes, with a standard deviation of 14.0 minutes. What is the 99% confidence interval (z-score = 2.58) for the number of minutes that an adult spends surfing the Internet per day?Remember, the margin of error, ME, can be determined using the formula .

Question illustration
A
49.1 minutes to 59.3 minutes
B
50.3 minutes to 58.1 minutes
C
54.2 minutes to 58.1 minutes
D
54.2 minutes to 59.3 minutes
40

According to the scatterplot below, which statement is correct?

Question illustration
A
The input, or dependent variable, is courses completed.
B
The output, or dependent variable, is credits needed to graduate.
C
The input, or independent variable, is credits needed to graduate.
D
The output, or independent variable, is courses completed.

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