APS4-2 Random Variables

Last updated over 4 years ago
9 questions
4

Classify each variable as a discrete or continuous random variable

  • The Friday night attendance at a football game
  • The age of a female
  • The number of children in a family
  • The amount of sugar in an orange
  • Discrete
  • Continuous
  • None
2

In a probability distribution, the Probability must satisfy which two requirements?

1

The table below shows the probability distribution for the number of tails (X) in five tosses of a fair coin.

What is the expected value of X?

1

Suppose that the distribution of a set of scores has a mean of 47 and a standard deviation of 14. If 4 is added to each score, what will be the mean and the standard deviation of the distribution of new scores?

1

Let the random variable X represent the profit made on a randomly selected day by a certain store. Assume that X is Normal with mean $360 and standard deviation $50. What is P(X > $400)?

2

Picard Partners is planning a major investment. The amount of profit X is uncertain but a probabilistic estimate gives the following distribution (in millions of dollars)
Find the mean (expected value) of X.

2

Picard Partners is planning a major investment. The amount of profit X is uncertain but a probabilistic estimate gives the following distribution (in millions of dollars)
Interpret the mean (expected value) of X that you found in the previous question.

2

Picard Partners is planning a major investment. The amount of profit X is uncertain but a probabilistic estimate gives the following distribution (in millions of dollars)
Find the standard deviation of X.

2

Picard owes its source of capital a fee of $200,000 plus 10% of the profits X. So the firm actually retains Y = 0.9X – 0.2 from the investment. Use a linear transformation of your results in (a) and (b) to find the mean and standard deviation for Y.