Question 1 of 25
1.0 Points
A scatterplot allows one to see:
A.whether there is any relationship between two variables
B.what type of relationship there is between two variables
C.Both (a) and (b) are correct
D.Neither (a) nor (b) is correct Reset Selection

Question 2 of 25
1.0 Points
In a recent study, the following data were obtained in response to the question, “Do you favor recycling in your neighborhood?”

 Males Females Total
Yes 25 30 55
No 15 10 25
No Opinion 10 10 20
Total 50 50 100

If a person is picked at random, what is the probability that the person is either male or has no opinion regarding recycling?
A.3/5
B.3/10
C.4/5
D.7/10

Question 3 of 25
1.0 Points
If two events are mutually exclusive, what is the probability that one or the other occurs?
A.0.50
B.0.25
C.1.00
D.Cannot be determined from the information given.
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Question 4 of 25
1.0 Points
The following data were obtained from a survey of college students. The variable X represents the number of non-assigned books read during the past six months.

x P (X=x)
0 0.2
1 0.25
2 0.2
3 0.15
4 0.1
5 0.1

What is the expected value of X?
A.3.65
B.6.25
C.1.20
D.2.0
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Question 5 of 25
1.0 Points
Find the variance of the following probability distribution.

X P(X)
1 0.30
2 0.15
3 0.05
4 0.25
5 0.25

A.1.73
B.1.61
C.2.60
D.1.27
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Question 6 of 25
1.0 Points
A drug is reported to benefit 40% of the patients who take it. If 6 patients take the drug, what is the probability that 4 or more patients will benefit?
A.0.667
B.0.862
C.0.138
D.0.179
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Part 4 of 9 –

Question 7 of 25
1.0 Points
The standard deviation of a probability distribution is a:
A.measure of skewness of the distribution
B.measure of central location
C.measure of relative likelihood
D.measure of variability of the distribution
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Question 8 of 25
1.0 Points
If the value of the standard normal random variable Z is positive, then the original score is where in relationship to the mean?
A.one standard deviation higher than the mean
B.equal to the mean
C.to the right of the mean
D.to the left of the mean
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Question 9 of 25
1.0 Points
The average height of flowering cherry trees in a nursery is 11 feet. If the heights are normally distributed with a standard deviation of 1.6, find the probability that a randomly selected cherry tree in this nursery is less than 13 feet tall.
A. 0.67
B.0.89
C.0.95
D.0.11 Reset Selection

Question 10 of 25
1.0 Points
If Z is a standard normal random variable, then the value z for which P(-z < Z < z) equals 0.8764 is
A.1.16
B.1.54
C.3.08
D.0.3764

 

Question 11 of 25
1.0 Points
The theorem that states that the sampling distribution of the sample mean is approximately normal when the sample size n is reasonably large is known as the:
A.point estimate theorem
B.central limit theorem
C.simple random sample theorem
D.central tendency theorem Reset Selection

Question 12 of 25
1.0 Points
The mean of a probability distribution can be:
A.a positive number
B.a negative number
C.zero
D.all of the above Reset Selection

Part 5 of 9 –

Question 13 of 25
1.0 Points
The histogram below represents scores achieved by 250 job applicants on a personality profile.
Half of the job applicants scored below what value? Place your answer in the blank. Do not use any stray symbols. For example, 123 would be a legitimate answer.

Part 6 of 9 –

Question 14 of 25
1.0 Points
In February 2002 the Argentine peso lost 70% of its value compared to the United States dollar. This devaluation drastically raised the price of imported products. According to a survey conducted by AC Nielsen in April 2002, 68% of the consumers in Argentina were buying fewer products than before the devaluation, 24% were buying the same number of products, and 8% were buying more products. Furthermore, in a trend toward purchasing less-expensive brands, 88% indicated that they had changed the brands they purchased. Suppose the following complete set of results were reported. Use the following data to answer this question.

Number of Products Purchased

Brands Purchased Same Changed Total
Fewer 10 262 272
Same 14 82 96
More 24 8 32
Total 48 352 400

What is the probability that a consumer selected at random purchased the same number or more products than before? Place your answer, rounded to 4 decimal places, in the blank.

Question 15 of 25
1.0 Points
It has been reported that 3% of all cars on the highway are traveling at speeds in excess of 70 mph. If the speeds of four random automobiles are measured via radar, what is the probability that at least one car is going over 70 mph? Place your answer, rounded to four decimal places, in the space.

Part 7 of 9 –

Question 16 of 25
1.0 Points
The Big Triple at the local racetrack consists of picking the correct order of finish of the first three horses in the ninth race. If there are 12 horses entered in today’s ninth race, how many Big Triple outcomes are possible? Place your answer, as a whole number—no decimal places—in the blank. For example 667 would be a legitimate entry.

Question 17 of 25
1.0 Points
An urn contains 12 balls identical in every respect except their color. There are 3 red balls, 7 green balls, and 2 blue balls. You draw two balls from the urn, but replace the first ball before drawing the second. Find the probability that the first ball drawn is red and the second ball drawn is green. Place your answer, rounded to 4 decimal places, in the blank. For example, 0.4567 would be a legitimate entry.

Part 8 of 9 –

Question 18 of 25
1.0 Points
Suppose that the average weekly earnings for employees in general automotive repair shops is $450, and that the standard deviation for the weekly earnings for such employees is $50. A sample of 100 such employees is selected at random.

Find probability that the mean of the sample is less than $445. Place your answer, rounded to 4 decimal places, in the blank. For example, 0.2345 would be a legitimate entry.

Question 19 of 25
1.0 Points
A Wendy’s fast-food restaurant sells hamburgers and chicken sandwiches. On a typical weekday, the demand for hamburgers is normally distributed with a mean of 450 and standard deviation of 80 and the demand for chicken sandwiches is normally distributed with a mean of 120 and standard deviation of 30.

How many hamburgers must the restaurant stock to be 99% sure of not running out on a given day? Place you answer, rounded to the nearest whole number in the blank. For example, 345 would be a legitimate entry.

Question 20 of 25
1.0 Points
A set of final exam scores in an organic chemistry course was found to be normally distributed, with a mean of 73 and a standard deviation of 8.

What is the probability of getting a score of 68 or less on this exam? Place your answer, rounded to 4 decimal places in the blank. For example, 0.3456 would be a legitimate entry.

Question 21 of 25
1.0 Points
A set of final exam scores in an organic chemistry course was found to be normally distributed, with a mean of 73 and a standard deviation of 8.

What is the probability of getting a score between 65 and 89 on this exam? Place your answer, rounded to 4 decimal places in the blank. For example, 0.3456 would be a legitimate entry.

Question 22 of 25
1.0 Points
Scores on a mathematics examination appear to follow a normal distribution with mean of 65 and standard deviation of 15. The instructor wishes to give a grade of “C” to students scoring between the 60th and 70th percentiles on the exam.

What score represents the 60th percentile score on the mathematics exam? Place your answer in the blank, rounded to a whole number. For example, 62 would be a legitimate entry.

Question 23 of 25
1.0 Points

Suppose that the average weekly earnings for employees in general automotive repair shops is $450, and that the standard deviation for the weekly earnings for such employees is $50. A sample of 100 such employees is selected at random.

Find the probability that the mean of the sample is between $445 and $455. Place your answer, rounded to 4 decimal places, in the blank. For example, 0.2345 would be a legitimate entry.

Part 9 of 9 –

Question 24 of 25
1.0 Points
Using the standard normal curve, the Z- score representing the 10th percentile is 1.28.
True
False
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Question 25 of 25
1.0 Points
A random variable X is normally distributed with a mean of 100 and a variance of 25. Given that X = 110, its corresponding Z- score is 0.40.
True
False
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