1. We interviewed 400 California licensed drivers drawn at random from California

DMV (Department of Motor Vehicles) records. The average number of speeding

tickets issued to the 400 is 5.3 and the SD is 0.2. What is a 68% confidence interval for the average of all California drivers?

A. The interval from 1.3 to 9.3

B. The interval from 4.3 to 6.3

C. The interval from 5.1 to 5.5

D. The interval from 5.20 to 5.40

E. The interval from 5.29 to 5.31

2. What is the best definition for inference in the context of statistics?

A. Calculating the chance of getting a sample statistic in a

specified range around the expected value of the population.

B. Generalizing a sample statistic to the population parameter.

C. Choosing the best unbiased sample from the population.

D. Distinguishing the population parameter from the sample statistic.

E. Estimating the minimum sample size necessary to accurately

capture the population parameter.

 

3. A fraternity is holding a lottery. Each ticket costs $1. 2000 tickets in total are sold.

The prize structure is as follows: a first prize of $200, a second prize of $50, ten

third prizes of $10 each, and ten fourth prizes of $5 each. Suppose you purchase one ticket. What is your expected net gain?

A. about -1 dollar

B. about -80 cents

C. about 20 cents

D. about 9 dollars

E. about 18 dollars

 

 

4. What is the best way to protect a survey from bias?

A. Use a probability method like simple random sampling to pick the sample.

B. Use quota sampling methods to pick a sample which resembles the population in key ways.

C. Try to minimize the standard deviation because this influences the size of the standard error.

D. Try to increase sample size in order to increase accuracy.

E. Try to get the highest response rate possible from a sample.

 

5. Suppose it is known that 85% of American mothers say "yes" when

asked if they would like their children to get married someday. We'd like to know more

details about why these moms feel the way they do so we decide to draw a random

sample of size 16 from the population of American moms for a detailed interview.

 

A) What is the expected value for the sample percentage and what is the standard

error for the sample percentage?

 

 

 

 

 

 

B) What is the chance that our sample has between 70% and 89% of these moms

saying "yes"?

 

 

 

 

 

 

 

6. Suppose the Chancellor of the university states that a statistical study has indicated that "With 95% confidence, the average IQ scores of UCLA undergraduates is between 105 and 135 IQ points." Since you attend UCLA and have now taken statistics, your family wishes to know what this statement means. How would you interpret the chancellor's statement for your family?

 

You are in Las Vegas, NV and you feel like betting on some upcoming sporting events.

Since you don't know anything about sports or sports betting, you decide to pick 10 teams at random. Unfortunately for you, Las Vegas oddsmakers (i.e. the people who determine the payoffs) know a lot about sports and sports betting. Picking 10 teams at random is like drawing tickets from an infinitely large box where 40% of the tickets have a +$1 and 60% of the tickets have a -$1.10 written on them. If your team wins, you get $1 and if they lose, you pay $1.10.

7. What is your expected total winnings after the10 games are played and the results are in?

 

 

 

 

 

 

 

8. What is the standard error of the expected total winnings from these 10 games?

 

 

 

 

 

 

 

 

9. Your friend accompanied you to Vegas and also bet on 10 games. Her total

winnings after the games were played was $3. When asked how she could have won in Vegas, she replied that she is really lucky. What is the chance of getting total winnings of $3 or higher?