Statistics And Probability Exam Quiz!

20 Questions | Total Attempts: 113

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Statistics And Probability Exam Quiz!

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Questions and Answers
  • 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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