Mean and Variance of Random Variable-Module 2

Which of the following notations is equivalent to the mean of the probability?

• none of the above

Which formula is appropriate to use in finding the mean of a discrete random

variable?

• E(x) = μx = ∑ x ∙ P(x)

• E(x) = μx = ∑ x + P(x)

• E(x) = μx = ∑ x ∙ P(x)^2

What can we generate if we take the squares of standard deviation?

• Expected Value

• Mean Value

• Probability value

• Variance

Which of the following is TRUE about the value of the mean of a discrete random

variable?

• Mean value is always equal to 1.

• Mean value cannot be negative.

• Mean value is equal to the expected value.

• Mean, Variance, and Standard Deviation are equal.

Which of the following most likely shows the largest possible variance or variability?

• number of girls in a randomly selected three-child family

• number of newborn babies per minute

• number of cookies inside a 133 grams pack from different branch of 7-11

  stores

• number of patients who are positive with COVID-19 in different hospitals

To which of the following concepts refer to this statement, “the sum of the product

of each value of a discrete random variable and its corresponding probability”?

• Probability Distribution

• Variance of Discrete Probability Distribution

• Standard Deviation of Discrete Probability Distribution

• Mean or Expected Value of Discrete Probability Distribution

Which of the following is also equal to the square root of the variance?

• mean

• median

• probability

• standard deviation

Which of the following data most likely shows the smallest possible variance or

variability?

• number of books in different branch of a bookstore

• number of books inside a pack bag of grade 11 students

• number of books inside the library of different SHS

• number of books inside the library of different households