Probability and Statistics Quiz

Which of the following statements illustrates a continuous random variable?

• Continuous random variable

• The average distance traveled by a tricycle in a month

• The number of motorcycles owned by a randomly selected household

• The number of girls taller than 5 feet in a random sample of 6 girls

The Grade 11 learners decided to play two 6-sided dice. What is the probability of rolling a 4 or 7?

• 9/36

• 1/6

• 5/36

• 2/9

Suppose two coins are tossed. Let X be the random variable representing the number of heads that occur. What are the values of random variable X?

• 0

• 0,1

• 0,1,2

• 0,1,2,3

Which of the following tables illustrates a probability distribution?

• X P(X) 0 2/4 1 1/4 2 2/4

• X P(X) 0 2/6 1 4/6 2 2/6

• X P(X) 0 2/5 1 1/5 2 2/5

• X P(X) 0 1/8 1 2/8 2 3/8

The probabilities that a student will buy 1, 2, 3, and 4 units in an apple store are 18, 28, 28 and 38 respectively. What is the average number of units that a student will buy?

• 2.88

• 2.89

• 2.90

• 2.91

The total area of the curve under the normal distribution is

• 0.68

• 0.95

• 0.997

• 1.00

The mean number of defective parts produced by a machine in a day is 2.2. What does it mean?

• The number of defective parts produced by a machine in one day is 2.2.

• The average number of defective parts that a machine produces in one day is 2.2.

• The machine is not producing non-defective items.

• The machine is producing defective items.

A bakeshop owner wanted to determine the average number of boxes of pandesal that are delivered each day. Find the mean of the probability distribution shown to help the bakeshop owner.

• 5.45

• 6.45

• 6.5

• 7

In a standard normal distribution, what percent of the area falls below the mean?

• 95%

• 90%

• 68%

• 50%

A university admission test which is normally distributed has a mean of 83 and a standard deviation of 4. If Melbabes got 91, what is the z-value that corresponds to her raw score?

• z = -2

• z = -1

• z = 1

• z = 2