Part 1 of 9 - 1.0/ 1.0 Points
Question 1 of 25 1.0/ 1.0 Points
A histogram that is positively skewed is also called
A.skewed to the

... [Show More] right
B.balanced
C.skewed to the left
D.symmetric
Answer Key:
Part 2 of 9 - 2.0/ 2.0 Points
Question 2 of 25 1.0/ 1.0 Points
If A and B are mutually exclusive events with P(A) = 0.70, then P(B):
A.can be any value between 0 and 1
B.cannot be larger than 0.30
C.cannot be determined with the information given
D.can be any value between 0 and 0.70
Answer Key:
Question 3 of 25 1.0/ 1.0 Points
If two events are mutually exclusive, what is the probability that both occur at the same time?
A.1.00
B.Cannot be determined from the information given.
C.0.00
D.0.50
Answer Key:
Part 3 of 9 - 3.0/ 3.0 Points
Question 4 of 25 1.0/ 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 0 1 2 3 4 5
P (X=x) 0.20 0.25 0.20 0.15 0.10 0.10
What is the standard deviation of X?
A.1.24
B.3.24
C.1.58
D.2.0
Answer Key:
Question 5 of 25 1.0/ 1.0 Points
In one town 33% of the households have a vehicle with all-wheel drive. If 4 households are selected at random, what is the probability that all 4 have vehicles with all-wheel drive?
A.0.0825
B.0.4662
C.0.0119
D.0.33
Answer Key:
Question 6 of 25 1.0/ 1.0 Points
A discrete probability distribution:
A.is a tool that can be used to incorporate uncertainty into models
B.can be estimated from long-run proportions
C.lists all of the possible values of the random variable and their corresponding probabilities
D.is the distribution of multiple random variables
Answer Key:
Part 4 of 9 - 6.0/ 6.0 Points
Question 7 of 25 1.0/ 1.0 Points
Given that Z is a standard normal random variable, P(-1.0 < Z < 1.5) is
A.0.8413
B.0.9332
C.0.0919
D.0.7745
Answer Key:
Question 8 of 25 1.0/ 1.0 Points
In a normal distribution, changing the standard deviation:
A.shifts the curve left or right
B.makes the curve more or less spread out
C.splits the distribution to two curves
D.makes the curve more robust
Answer Key:
Question 9 of 25 1.0/ 1.0 Points
The standard normal distribution has a mean of ___ and standard deviation of ___, respectively.
A.0 and 1
B.1 and 1
C.1 and 0
D.0 and 0
Answer Key:
Question 10 of 25 1.0/ 1.0 Points
One reason for standardizing random variables is to measure variables with:
A.different means and standard deviations on a single scale
B.different means and standard deviations on a non-standard scale
C.similar means and standard deviations on two scales
D.dissimilar means and similar standard deviations in like terms
Answer Key:
Question 11 of 25 1.0/ 1.0 Points
Given that the random variable X is normally distributed with a mean of 80 and a standard deviation of 10, P(85 < X < 90) is
A.0.3413
B.0.1915
C.0.1498
D.0.5328
Answer Key:
Question 12 of 25 1.0/ 1.0 Points
The standard deviation of a probability distribution must be:
A.a negative number
B.a nonnegative number
C.a number between 0 and 1
D.less than the value of the mean
Answer Key:
Part 5 of 9 - 0.0/ 1.0 Points
Question 13 of 25 0.0/ 1.0 Points
Accepted characters: numbers, decimal point markers (period or comma), sign indicators (-), spaces (e.g., as thousands separator, 5 000), "E" or "e" (used in scientific notation). NOTE: For scientific notation, a period MUST be used as the decimal point marker.
Complex numbers should be in the form (a + bi) where "a" and "b" need to have explicitly stated values.
For example: {1+1i} is valid whereas {1+i} is not. {0+9i} is valid whereas {9i} is not.
The following data represent the number of children in a sample of 10 families from Chicago: 4, 2, 1, 1, 5, 3, 0, 1, 0, and 2.
Compute the mean number of children. Place your answer, rounded to two decimal places, in the blank. For example, 3.45 would be a legitimate entry. 2.77
Answer Key: 1.90
Part 6 of 9 - 0.0/ 2.0 Points
Question 14 of 25 0.0/ 1.0 Points
Accepted characters: numbers, decimal point markers (period or comma), sign indicators (-), spaces (e.g., as thousands separator, 5 000), "E" or "e" (used in scientific notation). NOTE: For scientific notation, a period MUST be used as the decimal point marker.
Complex numbers should be in the form (a + bi) where "a" and "b" need to have explicitly stated values.
For example: {1+1i} is valid whereas {1+i} is not. {0+9i} is valid whereas {9i} is not.
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 0 1 2 3 4 5 6
P (X=x) 0.55 0.15 0.10 0.10 0.04 0.03 0.03
What is the expected value of X? Place your answer, rounded to two decimal places in the blank. For example, 4.56 would be a legitimate entry. 2.62
Answer Key: 1.14
Question 15 of 25 0.0/ 1.0 Points
Accepted characters: numbers, decimal point markers (period or comma), sign indicators (-), spaces (e.g., as thousands separator, 5 000), "E" or "e" (used in scientific notation). NOTE: For scientific notation, a period MUST be used as the decimal point marker.
Complex numbers should be in the form (a + bi) where "a" and "b" need to have explicitly stated values.
For example: {1+1i} is valid whereas {1+i} is not. {0+9i} is valid whereas {9i} is not.
Suppose that the probability that a new medication will cause a bad side effect is 0.03. If this medication is given to 150 people, what is the probability that more than three of them will experience a bad side effect? Place your answer, rounded to 4 decimal places, in the blank. For example, 0.1776 would be a legitimate answer. 0.1687
Answer Key: 0.6500|0.6700
Part 7 of 9 - 0.0/ 2.0 Points
Question 16 of 25 0.0/ 1.0 Points
Accepted characters: numbers, decimal point markers (period or comma), sign indicators (-), spaces (e.g., as thousands separator, 5 000), "E" or "e" (used in scientific notation). NOTE: For scientific notation, a period MUST be used as the decimal point marker.
Complex numbers should be in the form (a + bi) where "a" and "b" need to have explicitly stated values.
For example: {1+1i} is valid whereas {1+i} is not. {0+9i} is valid whereas {9i} is not.
Suppose that a marketing firm sends questionnaires to two different companies. Based on historical evidence, the marketing research firm believes that each company, independently of the other, will return the questionnaire with a probability of 0.30. What is the probability that neither of the questionnaires will be returned? Place your answer, rounded to 2 decimal places, in the blank. For example, 0.23 is a legitimate entry. 0.42
Answer Key: 0.49
Question 17 of 25 0.0/ 1.0 Points
Accepted characters: numbers, decimal point markers (period or comma), sign indicators (-), spaces (e.g., as thousands separator, 5 000), "E" or "e" (used in scientific notation). NOTE: For scientific notation, a period MUST be used as the decimal point marker.
Complex numbers should be in the form (a + bi) where "a" and "b" need to have explicitly stated values.
For example: {1+1i} is valid whereas {1+i} is not. {0+9i} is valid whereas {9i} is not.
An ice cream vendor sells three flavors: chocolate, strawberry, and vanilla. Forty five percent of the sales are chocolate, while 30% are strawberry, with the rest vanilla flavored. Sales are by the cone or the cup. The percentages of cones sales for chocolate, strawberry, and vanilla, are 75%, 60%, and 40%, respectively. For a randomly selected sale, define the following events:
= chocolate chosen
= strawberry chosen
= vanilla chosen
= ice cream on a cone
ice cream in a cup
Find the probability that the ice cream was chocolate flavor, given that it was sold on a cone. Place your answer, rounded to 4 decimal places, in the blank. For exampe, 0.3456 would be a legitimate entry. 0.2915
Answer Key: 0.5466
Part 8 of 9 - 5.0/ 6.0 Points
Question 18 of 25 1.0/ 1.0 Points
Accepted characters: numbers, decimal point markers (period or comma), sign indicators (-), spaces (e.g., as thousands separator, 5 000), "E" or "e" (used in scientific notation). NOTE: For scientific notation, a period MUST be used as the decimal point marker.
Complex numbers should be in the form (a + bi) where "a" and "b" need to have explicitly stated values.
For example: {1+1i} is valid whereas {1+i} is not. {0+9i} is valid whereas {9i} is not.
In a particular region of Cape Cod, it is known that lobstermen trap on average of 32 pounds of lobster per day with a standard deviation of four pounds. If a random sample of 30 lobster fishermen is selected, what is the probability that their average catch is less than 31.5 pounds?
Place your answer, rounded to four decimal places, in the blank. 0.2468 When entering your answer do not use any labels or symbols other than a decimal point. Simply provide the numerical value. For example, 0.1234 would be a legitimate entry.
Answer Key: 0.1968|0.2968
Question 19 of 25 0.0/ 1.0 Points
Accepted characters: numbers, decimal point markers (period or comma), sign indicators (-), spaces (e.g., as thousands separator, 5 000), "E" or "e" (used in scientific notation). NOTE: For scientific notation, a period MUST be used as the decimal point marker.
Complex numbers should be in the form (a + bi) where "a" and "b" need to have explicitly stated values.
For example: {1+1i} is valid whereas {1+i} is not. {0+9i} is valid whereas {9i} is not.
A popular retail store knows that the purchase amounts by its customers is a random variable that follows a normal distribution with a mean of $30 and a standard deviation of $9.
What is the probability that a randomly selected customer will spend less than $15 at this store? Place your answer, rounded to 4 decimal places, in the blank. For example, 0.3456 would be a legitimate entry. 0.6075
Answer Key: 0.0378|0.0578
Question 20 of 25 1.0/ 1.0 Points
Accepted characters: numbers, decimal point markers (period or comma), sign indicators (-), spaces (e.g., as thousands separator, 5 000), "E" or "e" (used in scientific notation). NOTE: For scientific notation, a period MUST be used as the decimal point marker.
Complex numbers should be in the form (a + bi) where "a" and "b" need to have explicitly stated values.
For example: {1+1i} is valid whereas {1+i} is not. {0+9i} is valid whereas {9i} is not.
Mrs. Smith's reading class can read a mean of 175 words per minute with a standard deviation of 20 words per minute. The top 3% of the class is to receive a special award. Assuming that the distribution of words read per minute are normally distributed, what is the minimum number of words per minute a student would have to read in order to get the award? Place your answer, rounded to the nearest whole number, in the blank. 213 When entering your answer do not use any labels or symbols. Simply provide the numerical value. For example, 123 would be a legitimate entry.
Answer Key: 210|216
Question 21 of 25 1.0/ 1.0 Points
Accepted characters: numbers, decimal point markers (period or comma), sign indicators (-), spaces (e.g., as thousands separator, 5 000), "E" or "e" (used in scientific notation). NOTE: For scientific notation, a period MUST be used as the decimal point marker.
Complex numbers should be in the form (a + bi) where "a" and "b" need to have explicitly stated values.
For example: {1+1i} is valid whereas {1+i} is not. {0+9i} is valid whereas {9i} is not.
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. 0.1587
Answer Key: 0.1087|0.2087
Question 22 of 25 1.0/ 1.0 Points
Accepted characters: numbers, decimal point markers (period or comma), sign indicators (-), spaces (e.g., as thousands separator, 5 000), "E" or "e" (used in scientific notation). NOTE: For scientific notation, a period MUST be used as the decimal point marker.
Complex numbers should be in the form (a + bi) where "a" and "b" need to have explicitly stated values.
For example: {1+1i} is valid whereas {1+i} is not. {0+9i} is valid whereas {9i} is not.
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. 0.8185
Answer Key: 0.7686|0.8686
Question 23 of 25 1.0/ 1.0 Points
Accepted characters: numbers, decimal point markers (period or comma), sign indicators (-), spaces (e.g., as thousands separator, 5 000), "E" or "e" (used in scientific notation). NOTE: For scientific notation, a period MUST be used as the decimal point marker.
Complex numbers should be in the form (a + bi) where "a" and "b" need to have explicitly stated values.
For example: {1+1i} is valid whereas {1+i} is not. {0+9i} is valid whereas {9i} is not.
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. 0.2160
Answer Key: 0.2160|0.3160
Part 9 of 9 - 1.0/ 2.0 Points
Question 24 of 25 1.0/ 1.0 Points
Using the standard normal curve, the Z- score representing the 99th percentile is 2.326.
Answer Key:
Question 25 of 25 0.0/ 1.0 Points
The sampling distribution of the mean will have the same mean as the original population from which the samples were drawn. [Show Less]