Math 102 Midterm Reviewer

The table below shows the Probability Mass Function (PMF) of four coins that are tossed, where Z is the random variable representing the number of head. Which of the following statements are correct?

I. The probability of getting two heads is 0.375.

II. The total number of possible outcomes is 4.

III. The probability of getting all tails is equal to the probability of getting all heads.

IV. 0.0625 is the probability of getting three heads.

• I and II

• I and III

• II and III

• III and IV

Which of the following represents the amount of spread, dispersion, or variability of the items in a distribution?

• mean or expected value

• median and mode

• outcomes and probability distribution

• variance and standard deviation

1.       Which of the following is NOT TRUE about the properties of a Probability Mass Function?

• The probability outcome is between 0 and 1.

• The sum of all probabilities is 1.

• The listing of all possible outcomes is exhaustive.

• The outcome can occur at the same time.

Which among the following variables is an example of a Discrete Random Variable?

• the average amount of electricity consumed

• the amount of paint used in painting a building

• the average weight of female students

• the number of patients in a hospital

Which of the following distribution represents a probability distribution?

• The distribution with random variable X represents a probability distribution since the sum of all probability outcomes is 1.001.

• The distribution with random variable Y represents a probability distribution.

• Both tables are not in probability distribution.

• The table with random variable Y is not a probability distribution since it has a sum of 1.

Given the distribution with random variable X below, identify the probability of the given notation: P(0<X<3)

• 0.15

• 0.57

• 0.43

• 0.44

Supposed two coins are tossed consecutively and we are interested in the number of heads that will come out. Determine the values of the random variable H (number of heads).

• 0,2,3,4

• 0,1,2

• 0,1,2,3

• 0,1,2,3,4

Which of the following represents the average value of a random variable?

• Variance

• Median

• Standard Deviation

• Expected Value

How would you interpret a very small variance or standard deviation but not equal to zero?

• The values of the random variables are farther from the mean.

• The values of the random variables are nearer to the mean.

• The values of the random variables are equal to the mean.

• The values of the random variables have no relationship with the mean.

Given the probability mass function of a discrete random variable as shown in the table, what is the variance and standard deviation of the probability distribution?

• 1.71 & 2.94

• 1.60 & 2.94

• 2.94 & 1.71

• 2.94 & 1.60