Hypothesis Testing — Unit test Answers

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4

Veronique has a spinner with three sections of equal size, red (r), green (g), and blue (b).The spinner is spun twice. The sample space for the possible outcomes is S = {rr, rb, rg, gr, gg, gb, br, bg, bb}. If the number of times red is spun is the random variable, X, which graph represents the probability distribution?

A
A probability distribution has number of times on the x-axis and probability on the y-axis. The probability of 0 times is 0.43; 1 time is 0.43; 2 times is 0.1.
Option A
B
A probability distribution has number of times on the x-axis and probability on the y-axis. The probability of 0 times is 0.33; 1 time is 0.33; 2 times is 0.33.
Option B
C
A probability distribution has number of times on the x-axis and probability on the y-axis. The probability of 0 times is 0.55; 1 time is 0.32; 2 times is 0.11.
Option C
D
A probability distribution has number of times on the x-axis and probability on the y-axis. The probability of 0 times is 0.5; 1 time is 0.38; 2 times is 0.12.
Option D
10

A supervisor finds the mean number of miles that the employees in a department live from work. He finds and . Which statement must be true?

Question illustration
A
z37 is within 1 standard deviation of the mean.
B
z37 is between 1 and 2 standard deviations of the mean.
C
z37 is between 2 and 3 standard deviations of the mean.
D
z37 is more than 3 standard deviations of the mean.
11

The histogram below shows the average number of days per year in 117 Oklahoma cities where the high temperature was greater than 90 degrees Fahrenheit.Which is an accurate comparison?

Question illustration
A
The mean is likely greater than the median because the data is skewed to the right.
B
The mean is likely greater than the median because the data is skewed to the left.
C
The median is likely greater than the mean because the data is skewed to the right.
D
The median is likely greater than the mean because the data is skewed to the left.
12

Car insurance companies want to keep track of the average cost per claim. The current data in use for Auto Insurance R Us is an average of $2,200 for each claim with a standard deviation of $500. With this average, the company can stay competitive with rates but not lose money. However, the statistician for the company believes that the cost of the average claim has increased. He pulled 40 recent claims and found the average to be $2,350. Which most restrictive level of significance would suggest that the company should raise rates? Upper-Tail Valuesa5%2.5%1%Critical z-values1.651.962.58

A
1%
B
2.5%
C
5%
D
10%
13

Veronique has a spinner with three sections of equal size, red (r), green (g), and blue (b).The spinner is spun twice. The sample space for the possible outcomes is S = {rr, rb, rg, gr, gg, gb, br, bg, bb}. If the number of times red is spun is the random variable, X, which graph represents the probability distribution?

A
A probability distribution has number of times on the x-axis and probability on the y-axis. The probability of 0 times is 0.43; 1 time is 0.43; 2 times is 0.1.
Option A
B
A probability distribution has number of times on the x-axis and probability on the y-axis. The probability of 0 times is 0.33; 1 time is 0.33; 2 times is 0.33.
Option B
C
A probability distribution has number of times on the x-axis and probability on the y-axis. The probability of 0 times is 0.55; 1 time is 0.32; 2 times is 0.11.
Option C
D
A probability distribution has number of times on the x-axis and probability on the y-axis. The probability of 0 times is 0.5; 1 time is 0.38; 2 times is 0.12.
Option D
14

A researcher wants to survey people from different age groups to analyze voting patterns. Which type of survey will best accomplish this goal?

A
systematic random sampling
B
voluntary sampling
C
convenience sampling
D
stratified sampling
15

A gymnastics coach records the scores of a gymnast and develops the probability distribution below. What is the probability the gymnast scores a 9 or 9.5?Probability DistributionGymnastics Score: XProbability: P(X)50.025.50.0260.066.50.170.167.50.1480.188.50.189?9.50.02

A
0.02
B
0.04
C
0.12
D
0.14
16

Which set of population data is the least dispersed from its mean?

A
2, 3, 2, 9
B
4, 0, 4, 0
C
6, 2, 2, 2
D
9, 3, 5, 3
17

Voluntary sampling is one type of sampling method that is not probability based. This means that

A
each member of a population is equally likely to be chosen for the survey.
B
the results of the survey cannot reliably be extended and generalized.
C
the likelihood of a member of the population volunteering to be surveyed is not probable.
D
the results of the survey are not mathematically probable.
18

A normal distribution of data has a mean of 90 and a standard deviation of 18. What is the approximate z-score for the value 64?

A
–3.6
B
–1.4
C
1.4
D
3.6
19

Weston completed a hypothesis test and found that he could not reject the null hypothesis. Which of the following is a valid reason for his conclusion?

A
The z-statistic is less than 0.
B
The z-statistic lies in the critical region.
C
The z-statistic is greater than 0.
D
The z-statistic lies outside the critical region.
20

Vladimir rolls a six-sided number cube 36 times. If getting a 3 is a success, what is the probability of a success?

A
One-sixth
Option A
B
One-third
Option B
C
Two-thirds
Option C
D
Five-sixths
Option D

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