# Statistics And Probability Exam Quiz!

20 Questions | Total Attempts: 113  Settings  .

• 1.
For Pearson’s correlation, if X increases Y increases, and when X decreases Y you don’t know. Pearson’s r should be close to which of the below values?
• A.

R=-1

• B.

R=1

• C.

R=0

• D.

I can't Know

• 2.
Suppose all salaries in a company are normally distributed, with a mean of \$70,000 and a standard deviation of \$10,000. If all salaries are doubled. What is the new mean and standard deviation?
• A.

Mean = 140,000 and std = \$20,000

• B.

Mean = 70,000 and std = \$10,000

• C.

Mean = 140,000 and std = \$10,000

• D.

Mean = 120,000 and std = \$15,000

• 3.
Consider a ball that is kicked by a mean of 10 feet in the right direction and with a standard deviation of 1 foot, it is then kicked back in the opposite direction towards where it was started by 5 feet but with a standard deviation of 0.5. What are the mean and standard deviation of this new Gaussian distribution of the distance?
• A.

Mean = 5, std= 0.5

• B.

Mean = 10, std= 1.5

• C.

Mean = 15, std= 1.5

• D.

Mean = 5, std= 1.118

• 4.
Covariance indicates the strength of the linear relationship between variables.
• A.

True

• B.

False

• 5.
Correlation measures both the strength and direction of the non-linear relationship between two variables.
• A.

True

• B.

False

• 6.
IQ is distributed with a mean of 100 and a variance of 225. What is the standard score for IQ of 130?
• A.

2

• B.

0.13

• C.

30

• D.

15

• 7.
Is the below relationship Linear and Exact?
• A.

True

• B.

False

• 8.
Given a Summer/Winter classification problem: Winter is 165 days and Summer is 200 days. The temperature is uniformly distributed between 5 - 25 degrees in Winter and 22 - 24 in Summer. What is the classification of the day that temperature is 23 degrees?
• A.

Summer

• B.

Winter

• 9.
You are given a revolver with six slots. There are two adjacent bullets. You have to shoot twice and are given the chance to rotate the cylinder randomly in-between. How do you maximize your chance of survival?
• A.

Rotate cylinder

• B.

Do not rotate cylinder

• C.

It doesn't matter, as survival chance is the same in both cases

• D.

The question doesn't give all information required to answer the question

• 10.
Set S consists of the numbers 4, 10, 12, 7, 19, 10, 5, and x. For what value of x will the mode, the median, and the mean all be equal?
• A.

13

• B.

17

• C.

21

• D.

42

• 11.
If the variance of a dataset is 50 and all data points are increased by 100% then what will be the variance?
• A.

50

• B.

100

• C.

200

• D.

25

• 12.
If you have a dataset with n observations and mean m. What will be the new mean if you add 5 to each data point?
• A.

M

• B.

M + 5

• C.

5

• D.

None of the above

• 13.
Given the following distribution Which of the following statements is true?
• A.

Mean < Median < Mode

• B.

Median < Mode < Mean

• C.

Mode < Median < Mean

• D.

Mode < Mean < Median

• 14.
What is the number of observations in a dataset with variance 5 if the sum of squared distances from the mean is 20?
• A.

4

• B.

5

• C.

20

• D.

100

• 15.
Rank the below correlation coefficient from lowest to highest coefficient.
• A.

B > A > C > D

• B.

B > C > D > A

• C.

B > C > A > D

• D.

A > B > C > D

• 16.
Given that we have a probability of rain = 0.2 on a given day. What is the probability of having rain at least 2 days during the week?
• A.

0.36

• B.

0.40

• C.

0.42

• D.

0.53

• 17.
Which statistical measurement is affected by outliers the most?
• A.

Range

• B.

Mean

• C.

Mode

• D.

Median

• 18.
You have n numbers that must sum to 10. How many degrees of freedom are there?
• A.

N

• B.

N + 1

• C.

N - 1

• D.

N/2

• 19.
Subtracting two Gaussian Distributions results in:
• A.

Mean is subtracted and standard deviation is added

• B.

Mean is subtracted and variance is added

• C.

Mean is subtracted and standard deviation is subtracted

• D.

Mean is subtracted and variance is subtracted

• 20.
Given a bag of marbles with 8 red marbles, 4 blue marbles, and 5 green marbles. Removing marbles one at a time from the bag, what is the likelihood of removing 4 marbles without removing a green marble?
• A.

50.2%

• B.

38.5%

• C.

70.6%

• D.

20.8%

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