MATH311 Statistics Quiz

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Question 1 of 25

1.0 Points

Which of the following correctly describes the relationship between a sample and a population?

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Part 2 of 9 -

Question 2 of 25

1.0 Points

The probability of an event and the probability of its complement always sum to:

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Question 3 of 25

1.0 Points

Three cards are drawn from a deck without replacement. What is the probability that all three cards are clubs?

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Part 3 of 9 -

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	0	1	2	3	4	5
P (X=x)	0.20	0.25	0.20	0.15	0.10	0.10

Find P( X > 1)

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Question 5 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

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Question 6 of 25

1.0 Points

In a small town, 60% of the households have dogs. If 5 households are randomly selected, what is the probability that at least 4 of them have dogs?

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Part 4 of 9 -

Question 7 of 25

1.0 Points

The standard deviation of a probability distribution must be:

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Question 8 of 25

1.0 Points

In a normal distribution, changing the standard deviation:

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Question 9 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

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Question 10 of 25

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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.

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Question 11 of 25

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The standard deviation of a probability distribution is a:

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Question 12 of 25

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The normal distribution is:

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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.

The histogram below represents scores achieved by 250 job applicants on a personality profile.

$The histogram below represents scores achieved by 250 job applicants on a personality profile.$

How many job applicants scored between 10 and 30? Place your answer in the blank. Do not use any stray symbols. For example, 123 would be a legitimate answer.

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