Statistics and Probability Exam Quiz!

Question 1

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?

Accepted Answer

m + 5

Answer

m

Answer

5

Answer

None of the above

Question 2

Rank the below correlation coefficient from lowest to highest coefficient.

Accepted Answer

B > A > C > D

Answer

B > C > D > A

Answer

B > C > A > D

Answer

A > B > C > D

Question 3

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?

Accepted Answer

Summer

Answer

Winter

Question 4

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?

Accepted Answer

mean = 140,000 and std = $20,000

Answer

mean = 70,000 and std = $10,000

Answer

mean = 140,000 and std = $10,000

Answer

mean = 120,000 and std = $15,000

Question 5

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?

Accepted Answer

13

Answer

17

Answer

21

Answer

42

Question 6

Is the below relationship Linear and Exact?

Accepted Answer

False

Answer

True

Question 7

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

Accepted Answer

4

Answer

5

Answer

20

Answer

100

Question 8

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

Accepted Answer

n - 1

Answer

n

Answer

n + 1

Answer

n/2

Question 9

Which statistical measurement is affected by outliers the most?

Accepted Answer

Mean

Answer

Range

Answer

Mode

Answer

Median

Question 10

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

Accepted Answer

False

Answer

True

Question 11

Covariance indicates the strength of the linear relationship between variables.

Accepted Answer

False

Answer

True

Question 12

A bag contains 8 red marbles, 4 blue marbles, and 5 green marbles. If you randomly draw 2 marbles from the bag without replacement, what is the probability that both marbles are red?

Accepted Answer

7/34

Answer

1/17

Answer

14/153

Answer

2/17

Question 13

Given the following distribution 

Which of the following statements is true?

Accepted Answer

Mode < Median < Mean

Answer

Mean < Median < Mode

Answer

Median < Mode < Mean

Answer

Mode < Mean < Median

Question 14

For Pearson&rsquo;s correlation, if X increases Y increases, and when X decreases Y you don&rsquo;t know. Pearson&rsquo;s r should be close to which of the below values?

Accepted Answer

r=0

Answer

r=-1

Answer

r=1

Answer

I can't Know

Question 15

Subtracting two Gaussian Distributions results in:

Accepted Answer

mean is subtracted and variance is added

Answer

mean is subtracted and standard deviation is added

Answer

mean is subtracted and standard deviation is subtracted

Answer

mean is subtracted and variance is subtracted

Question 16

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?

Accepted Answer

Do not rotate cylinder

Answer

Rotate cylinder

Answer

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

Answer

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

Question 17

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

Accepted Answer

2

Answer

0.13

Answer

30

Answer

15

Question 18

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

Accepted Answer

200

Answer

50

Answer

100

Answer

25

Question 19

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?

Accepted Answer

0.42

Answer

0.36

Answer

0.40

Answer

0.53

Question 20

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?

Accepted Answer

mean = 5, std= 1.118

Answer

mean = 5, std= 0.5

Answer

mean = 10, std= 1.5

Answer

mean = 15, std= 1.5

Statistics and Probability Exam Quiz! Live Quiz