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**The amount of time needed to run the Boston marathon is an example of which type of variable**

- From Mathematics, Statistics

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Question 1 of 25 1.0 Points

The amount of time needed to run the Boston marathon is an example of which type of variable?

A.qualitative

B.none of the above

C.discrete

D.continuous

Part 2 of 9 -

Question 2 of 25 1.0 Points

If two events are mutually exclusive, what is the probability that both occur at the same time?

A.0.00

B.0.50

C.1.00

D.Cannot be determined from the information given.

Question 3 of 25 1.0 Points

If A and B are mutually exclusive events with P(A) = 0.30 and P(B) = 0.40, then the probability that either A or B or both occur is:

A.0.30

B.0.10

C.0.12

D.0.70

Part 3 of 9 -

Question 4 of 25 1.0 Points

Find the variance of the following probability distribution.

X P(X)

1 0.10

2 0.35

3 0.10

4 0.15

5 0.30

A.1.44

B.2.06

C.1.76

D.1.2

Question 5 of 25 1.0 Points

There are two types of random variables, they are

A.discrete and continuous

B.real and unreal

C.complementary and cumulative

D.exhaustive and mutually exclusive

Question 6 of 25 1.0 Points

Suppose that 50 identical batteries are being tested. After 8 hours of continuous use, assume that a given battery is still operating with a probability of 0.70 and has failed with a probability of 0.30.

What is the probability that fewer than 25 batteries will last at least 8 hours?

A.0.0024

B.0.9991

C.0.0009

D.0.8967

Part 4 of 9 -

Question 7 of 25 1.0 Points

The standard deviation of is usually called the

A.standard error of the population

B.standard error of the sample

C.randomized standard error

D.standard error of the mean

Question 8 of 25 1.0 Points

Given that Z is a standard normal variable, the value z for which P(Z < z) = 0.2580 is

A.-0.70

B.-0.65

C.0.758

D.0.242

Question 9 of 25 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.0.5328

D.0.1498

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.1.54

B.0.3764

C.3.08

D.1.16

Question 11 of 25 1.0 Points

The mean of a probability distribution is a:

A.measure of skewness of the distribution

B.measure of relative likelihood

C.measure of central location

D.measure of variability of the distribution

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

Part 5 of 9 -

Question 13 of 25 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 sample of 150 students at a State University was taken after the final business statistics exam to ask them whether they went partying the weekend before the final or spent the weekend studying, and whether they did well or poorly on the final. The following table contains the result.

Did Well on Exam Did Poorly on Exam

Studying for Exam 60 15

Went Partying 22 53

If the sample is a good representation of the population, what percentage of those who did poorly on the final exam should we expect to have spent the weekend studying? Place your answer in the blank, rounded to 2 decimal places. Do not use a percentage sign (%). For example, 44.44 would be a legitmate answer.

Part 6 of 9 -

Question 14 of 25 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.

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.

Question 15 of 25 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 survey, 55% of the voters support a particular referendum. If 40 voters are chosen at random, and X is the number of voters that support this referendum, find the mean and variance of X. Place the mean in the first blank and place the variance in the second blank.

Part 7 of 9 -

Question 16 of 25 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.

Mothers Against Drunk Driving (MADD) is a very visible group whose main focus is to educate the public about the harm caused by drunk drivers. A study was recently done that emphasized the problem we all face with drinking and driving. Five hundred accidents that occurred on a Saturday night were analyzed. Two items noted were the number of vehicles involved and whether alcohol played a role in the accident. The numbers are shown below:

Number of Vehicles Involved

Did alcohol play a role? 1 2 3

Yes 60 110 30 200

No 40 215 45 300

100 325 75

Given that 3 vehicles were involved, what proportion of accidents involved alcohol? Place your answer, rounded to 2 decimal places, in the blank. For example. 0.23 is a legitimate entry.

Question 17 of 25 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 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

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 manufacturer of a new compact car claims the miles per gallon (mpg) for the gasoline consumption is mound shaped and symmetric with a mean of 25.9 mpg and a standard deviation of 9.5 mpg. If 30 such cars are tested, what is the probability the average mpg achieved by these 30 cars will be greater than 28? Place your answer, rounded to 4 decimal places, in the blank.

Question 19 of 25 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.

It has been observed that electrical connectors manufactured by Jolt Electrical Supply Company last an average of 18.2 months and follow a normal distribution with a standard deviation of 1.7 months. Jolt agrees to replace any connector that fails within 19 months. Out of 500 connectors sold, how many does Jolt expect to replace, on average? Place your answer, rounded to the nearest whole number, in the blank. For example, 123 would be a legitimate answer.

Question 20 of 25 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 mean weight of loads of coal placed in train cars by a loading machine is 43.0 tons with a standard deviation of 8.0 tons. Assuming that the weight of loads placed in the train cars by this loader are normally distributed, if a random sample of 9 loads is chosen for a weight check, find the probability that the mean weight of those loads is more than 40.60 tons.

Place your answer, rounded to four decimal places, in the blank. 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.

Question 21 of 25 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 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 chicken sandwiches 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 22 of 25 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 $20 or more at this store? Place your answer, rounded to 4 decimal places, in the blank. For example, 0.3456 would be a legitimate entry.

Question 23 of 25 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 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.

Part 9 of 9 -

Question 24 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

Reset Selection

Question 25 of 25 1.0 Points

Using the standard normal curve, the Z- score representing the 85th percentile is 0.67

True

False

**The amount of time needed to run the Boston marathon is an example of which type of variable**

- This Solution has been Purchased 3 time
- Submitted On 25 Dec, 2014 09:15:50

**AceTutor****Rating :**28**Grade :****A+****Questions :**0**Solutions :**832**Blog :**1**Earned :**$20923.75