Probability and Random Variables Quiz

In a local community, a couple was asked the questions, "Are you satisfied with the work of the current president?" If the husband and the wife both said "yes", the response is written as YY. If the husband said yes and the wife said "no", the response is YN. Let X be the number of "yes" responses, what are the possible values of the random variables?

• 0,1,2

• 1,2,3

• 2,3,4

• 1,1,2

If a coin is tossed, what are the possible values of the random variable for the number of tails?

• 0,1

• 0,1,2

• 1,2,3

• 0,1,2,3

Suppose you tossed three coins. What are the sample spaces for the experiment above?

• HHH, TTT

• TTT, HHH, TTH, THT, HTH

• TTT, HHH, HHT, THT, HTH

• TTT, TTH, THT, HTT, HHT, HTH, THH, HHH

What must be the value of the probability of each random variable?

• P(X) ≥ 0

• -1≤ P(X) ≤ 1

• 0≤ P(X) ≤ 1

• P(X) ≤ 1

Which of the following values is not the value of the probability of the random variable?

• 1.01

• 0.5

• 0.15

• 0.05

The following table shows the probability distribution of a discrete random variable X. Find the value of n.

• 0.15

• 0.25

• 0.45

• 0.6

The probabilities that a customer buys 5,8,9,12 and 15 items in a grocery store are 0.06, 0.14, 0.32, 0.28, and 0.20 respectively. Which probability distribution represents the given problem?

• 
• 
• 
• 

If the values of the random variable X are 0,1,2 and 3 where X represents the number of heads in tossing a coin thrice, what is the probability that three heads will come up?

• 1/2

• 3/8

• 1/4

• 1/8

Which of the following is NOT included in the process of calculating the mean of the discrete random variable X?

• Identify the correct probabilities for each x value.

• Multiply each x value by its probability.

• Get the summation of the product.

• Get the square root of the product.

If the variance of a probability distribution is 2.6 grams, what is the standard deviation?

• 1.61

• 1.16

• 1.06

• 1.01