Unit Test — Unit test Answers

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A fair, six-sided number cube has the numbers 2, 2, 4, 4, 6, 6 on its faces. Sarah rolls this number cube 10 times and records the number of times a 2 is rolled.Have the conditions for a binomial setting been met for this scenario?

A
Yes, all four conditions in BINS have been met.
B
No, the rolls of a number cube are not independent of one another.
C
No, this is not a fair number cube because each outcome shows on more than one face.
D
No, without any odd-numbered faces, we cannot determine the probability of rolling a 2.
8

Let A represent the battery life of a brand A laptop, and let B represent the battery life of a brand B laptop. The mean difference in battery life between these two brands of laptops, D = A – B, is –3.25 hours. What is the correct interpretation of this value?

A
On average, brand B gains 3.25 hours of battery life daily.
B
On average, brand A loses 3.25 hours of battery life daily.
C
Both brands are typically losing 3.25 hours of battery life daily.
D
On average, brand B’s battery life lasts 3.25 hours longer than brand A.
9

The owner of a local movie theater keeps track of the number of tickets sold in each purchase. The owner determines the probabilities based on these records. Let X represent the number of tickets bought in one purchase. The distribution for X is given in the table.

Question illustration
A
A histogram titled Movie tickets has x = number of tickets sold on the x-axis, and probability on the y-axis. 1, 0.55; 2, 0.20; 3, 0.17; 4, 0.06; 5, 0.02.
Option A
B
A histogram titled Movie tickets has x = number of tickets sold on the x-axis, and probability on the y-axis. 1, 0.02; 2, 0.17; 3, 0.20; 4, 0.55; 5, 0.06.
Option B
C
A histogram titled Movie tickets has x = number of tickets sold on the x-axis, and probability on the y-axis. 1, 0.17; 2, 0.55; 3, 0.20; 4, 0.06; 5, 0.02.
Option C
D
A histogram titled Movie tickets has x = number of tickets sold on the x-axis, and probability on the y-axis. 1, 0.02; 2, 0.17; 3, 0.55; 4, 0.20; 5, 0.06.
Option D
11

Standardized tests for certain subjects, given to high school students, are scored on a scale of 1 to 5. Let A represent the score on a randomly selected exam for subject A and let B represent the score on a randomly selected exam for subject B. The distributions of scores for each subject’s standardized tests are displayed in the table and the histograms.

Question illustration
A
Both distributions are roughly unimodal symmetric.
B
Subject A’s distribution is skewed right and subject B’s distribution is skewed left.
C
Subject A’s distribution is roughly unimodal symmetric and subject B’s distribution is skewed left.
D
Subject A’s distribution is roughly unimodal symmetric and subject B’s distribution is skewed right.
12

A local charity holds a carnival to raise money. In one activity, participants make a $3 donation for a chance to spin a wheel that has 10 spaces with the values, 0, 1, 2, 5, and 10. Whatever space it lands on, the participant wins that value. Let X represent the value of a random spin. The distribution is given in the table.

Question illustration
A
The probability of a random spin having a value of at most 5 is 0.8.
B
The probability of a random spin having a value of at least 5 is 0.2.
C
The probability of a random spin having a value lower than 5 is 0.8.
D
The probability of a random spin having a value higher than 5 is 0.1.
14

A large hotel has five elevators. On any given day, there is an 8% chance that one elevator is broken The elevators operate independently of one another. The Robertsons are staying in this hotel for five days. Let X represent the number of days one elevator is broken during their stay. What are the mean and standard deviation of X?

A
Mu Subscript x Baseline = 0.4, Sigma Subscript x Baseline = 0.074
Option A
B
Mu Subscript x Baseline = 0.4, Sigma Subscript x Baseline = 0.61
Option B
C
Mu Subscript x Baseline = 2.5, Sigma Subscript x Baseline = 1.92
Option C
D
Mu Subscript x Baseline = 4, Sigma Subscript x Baseline = 0.89
Option D
16

There are 16 students in a science class. Let X represent the number of students born on a Tuesday. Assuming birthdays in this class are independent of one another, what are the mean and standard deviation of X?

A
Mu Subscript x Baseline = 2.29, Sigma Subscript x Baseline = 1.40
Option A
B
Mu Subscript x Baseline = 3, Sigma Subscript x Baseline = 1.96
Option B
C
Mu Subscript x Baseline = 7, Sigma Subscript x Baseline = 1.51
Option C
D
Mu Subscript x Baseline = 13.71, Sigma Subscript x Baseline = 3.84
Option D

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