Calculate the expected value of a discrete random variable

Question

1. Question : In the application of Bayes' Theorem the sample information is combined with prior probabilities to obtain posterior probabilities.

• True
• False

2. Question : The actual weight of hamburger patties is an example of a continuous random variable.

• True
• False

3. Question : A student's grade on an examination was transformed to a z value which is negative. Therefore, we know that he scored

Student Answer: higher than 16% of the class.

• higher than 45% of the class.
• above the first quartile.
• below the mean.
• above the mean but below the median.

4. Question : The expected value of a discrete random variable is:

• ∑x p(x)
• n ·p ·q
• ∑(x - µx)2 p(x)

5. Question : The following formula: P(A U B) = P(A) + P(B) - P(A ∩ B) represents

• the conditional probability.
• the addition rule.
• independence.
• the multiplication rule.
• None of the above.

6. Question : A standard normal distribution has a mean of ____and standard deviation of ____

• zero, zero.
• zero, one.
• one, one.
• one, zero.

7. Question : A(n) __________ is a measure of the chance that an uncertain event will occur.

• experiment
• sample space
• probability
• complement
• population

8. Question : The MPG (mileage per gallon) for a mid-size car is normally distributed with a mean of 32 and a standard deviation of .8. What is the probability that the MPG for a selected mid-size car would be less than 33.2?

• 43.32%
• 6.68%
• 93.32%
• 86.64%
• 13.36%

9. Question : For a Poisson random variable the mean and the variance equal the average number of occurrences over the time interval (µx = ó2x = µ)

• True
• False

10. Question : In a statistical study, the random variable X = 1, if the house is colonial, and X = 0 if the house is not colonial, then it can be stated that the random variable is continuous.

• True
• False