1.1 Skills practice exam 2: chapters 3, 4, 5, & 6  (Page 2/3)

What is the distribution for the number of questions answered correctly when a student studies?

• a B(15, 0.80)
• b B(15, 0.25)
• c P(15)
• d P(6)

Suppose that a student does not study for the test but randomly guesses the answers. What is the probability that the student will answer 7 or 8 questions correctly?

• a 0.2951
• b 0.0524
• c 0.0131
• d Cannot determine

A downtown hotel determined the probability of finding X taxicabs waiting outside the hotel anytime between 5 PM and midnight. The information is shown in the table.

What is the average number of taxicabs that are expected to be waiting outside the hotel anytime between 5 PM and midnight?

• a 3.7
• b 3
• c 0
• d 15

. During the registration period for a new quarter, the De Anza College Registrar’s Office processes approximately 75 applications per hour, on the average. What is the probability that it will process more than 80 applications for a randomly chosen hour? (This is a Poisson problem. If you did not cover the Poisson Distribution, then skip this problem.)

• a 0.0379
• b 0.2589
• c 0.7411
• d 0.0248

Events S and T are:

• a mutually exclusive
• b independent
• c mutually exclusive and independent
• d neither mutually exclusive nor independent

Find P(S AND T)

• a 0.3450
• b 0.2500
• c 0.6900
• d 1

Find P(S OR T)

• a 0.6900
• b 1.19
• c 0.8450
• d 0

Based on data from the US Census Bureau the average age of US residents is 36.31 with a standard deviation of 21.99. The data is normally distributed. The notation for the distribution is:

• a X ~ N(36.31, 21.99)
• b X ~ N(21.99, 36.31)
• c X ~ B(36.31, 22)
• d X ~ U(0, 36.31)

In a binomial distribution we:

• a count the number of successes until a failure is obtained
• b count the number of trials until a success is obtained
• c count the number of successes in a finite number of trials
• d count the number of trials until the number of successes equals the number of failures

Certain stocks have a probability of 0.6 of returning a $100 profit. They also have a probability of 0.4 of having a loss of $300. Over the long run, what is the best thing to do to maximize your profit, and why?

• a Invest in the stocks because there is a greater probability of making money than losing money.
• b Do not invest in the stocks because the dollar amount for each loss is greater than the dollar amount for each gain.
• c Invest in the stocks because making $100 per stock is preferred to losing $300 per stock.
• d Do not invest in the stocks because the expected value is a loss.