STATS & PROB Q1 REVIEW

Which of the following is not a random variable?

• The heights of randomly-selected buildings in New York City.

• The number of children in randomly-selected households in the United States.

• The suit of a card randomly-selected from a 52-card deck.

• The amount of money won (or lost) by the next person to walk out of a casino in Las Vegas.

A small store keeps track of the number X of customers that make a purchase during the first hour that the store is open each day. Based on the records, X has the following probability distribution. The mean number of customers that make a purchase during the first hour that the store is open is:

• 2.0

• 2.9

• 2.5

• 3

A small store keeps track of the number X of customers that make a purchase during the first hour that the store is open each day. Based on the records, X has the following probability distribution. The standard deviation of customers that make a purchase during the first hour that the store is open is:

• 0.2

• 2.0

• 1.4

• 3.0

What is the variance of the distribution?

• 8.04

• 9.50

• 8.40

• 9.05

Which of the following is a discrete random variable?

• Number of Bags

• Distance traveled

• Height of the Tree

• Weight of all members in the house

Which of the following is a continuous random variable?

• Money inside the pocket

• Recording the number of points scored by a NBA team in each game

• Tossing a pair of fair coins

• Length of time it takes before a dolphin surfaces in the ocean to breath

Is the given function a PMF?

• Yes, because it passes the property 1 and 2 of PMF

• Yes, because it passes the property 2 of PMF.

• No, because it fails the property 2 of PMF.

• No, because it fails both property 1 and 2 of PMF.

Shuffle a deck of 52 cards. Turn over the top card. Put the card back in the deck, shuffle again. Repeat the process 10 times. Let X = the number of aces you observe. What type of distribution is involved in the situation?

• Binomial

• Hypergeometric

• Bernoulli

• Poisson

Find the area under the standard normal curve above z = -2.67.

• 0.0869

• 0.0008

• 0.9962

• 0.1234

Find the area under the normal distribution curve below Z=0.27.

• 0.3936

• 0.6064

• 0.3897

• 0.4892