1. If an experiment is run double-blind, then we would have given the treatment group a placebo.

2. The original NFIP study on the Salk Vaccine Trial was run double-blind.

3. When an impartial chance procedure is used to assign the subjects to treatment or control, the experiment is said to be:

4. By placing subjects into the treatment and control groups "at random", we are guarding against bias.

5. Choose the TRUE statement.

6. Choose the best study design.

7. Choose the most effective study:

8. Confounding means a difference between the treatment and control groups--other than the treatment--which affects the responses.

9. For the observational study on smoking, what was(were) the confounding factor(s)?

10. If the control group is comparable to the treatment group, apart from the treatment, then a difference in the responses of the two groups is likely to be due to:

11. Suppose in this experiment, for each subject, a coin is flipped, and the subject receives treatment only if the coin lands heads. In this scenario, the experiment can be categorized as:

12. A study that is not run double-blind always gives opposite results as one that was run double-blind.

13. When possible, a weighted average should be used to help with confounding factors.

14. Crowding on a histogram is determined by the

15. This table represents the distribution of 300 families by income in the U.S. in 1974. Class intervals include the left endpoint, but not the right. The histogram should be made such that the Income in thousands of Dollars is the horizontal scale.

Income Level Frequency Percent

0-2000 11 3.7

2000-4000 15 5

4000-7000 22 7.3

7000-10000 35 11.7

10000-16000 __ 12

16000-24000 __ __

24000-32000 70 23.3

32000-50000 55 18.3

50000 and over 5 1.7

When drawing this histogram, the height of the block from $2,000 to $4,000 will be:

1. This table represents the distribution of 300 families by income in the U.S. in 1974. Class intervals include the left endpoint, but not the right. The histogram should be made such that the Income in thousands of Dollars is the horizontal scale.

Income Level Frequency Percent

0-2000 11 3.7

2000-4000 15 5

4000-7000 22 7.3

7000-10000 35 11.7

10000-16000 __ 12

16000-24000 __ __

24000-32000 70 23.3

32000-50000 55 18.3

50000 and over 5 1.7

When drawing this histogram, the height of the block from $7,000 to $10,000 will be:

1. For histograms in the density scale,____.

2. Histograms are always symmetric.

3. Below is a table of the ages of people who attended a seminar on advanced statistics. There were 1000 people attending.

AgeRange(yrs) # of People Percentage of People

20 -25 200 ___

25-45 500 ___

45-55 ____ 30%

What percentage of the people are between 20 and 45 years of age?

1. For the given set of numbers, find the Root Mean Square: 57.9, 78, 96, 0, -14, 15, 3.

2. Find the SD for: -7, 10, 3, 0, 6, -9

3. For the following number set, find the average: 57.9, 78, 96, 0, -14, 15, 3.

4. For the given list, find the lower quartile: 188, 98, 41, 0, 68, 143, 193, 169.

5. The first quartile is the same as the ____ percentile.

6. If a set of numbers has an average of 15 and an SD of 3, and each number in the set is multiplied by 4, what will the SD of the new set of numbers be?

7. For the following set of numbers, find the outlier(s): 6, 58, 100, 56, 52, 49, 58, 65, 58, 59

8. A value is converted to standard units by seeing how many __ it is above or below the __.

9. The average monthly wage of employees in a company is $2,600 and the SD is $300. The president of the company decides to give each employee a raise of $250. The new SD will be:

10. Table 1: Selected percentiles for family income in the U.S. in 2004. 1 $0 10 $15,000 25 $29,000 50 $54,000 75 $90,000 90 $135,000 99 $430,000

11. The average on an exam is 70 and the SD is 20. What is the 90th percentile? (assume the scores are normally distributed) Choose the closest answer.

12. Find the area to the left of 2.3 under the normal curve.

13. Five measurements are taken and are: 59.5", 61.33", 60.55", 61.00", 59.8". Find the likely size of the chance error in a single measurement.

14. A die is tossed 5 times. What is the probability that a two shows only on the 5th toss?

15. Determine for the following box, whether number and shape are independent or dependent. The box has a triangle with a 3 in it, a square with a 2 in it, a square with a 3 in it, and a triangle with a 2 in it.

16. There are 5 Democrats, 6 Republicans, and 4 Independents in a room. Two people will be selected at random without replacement. The chance that both are Republicans is:

17. There are 10 workers and 2 administrators in a company meeting room. Two people will be selected at random without replacement. The chance that the second person is a worker given that the first person is an administrator is:

18. Two cards are drawn from a deck of cards. What is the probability that the first card is black and the second card is red?

19. A coin is tossed, and you win $1 if you get less than 40% heads. How many tosses should you make?

20. A die is tossed, and you win $1 if you get more than 14% 4s. How many tosses should you make?

21. A gambler plays roulette 300 times, betting $1 on a column (of 12 numbers) each time. A column pays 2 to 1, and there are 12 ways in 38 to win. Find the amount of money the gambler is expected to win.

22. A gambler plays roulette 300 times, betting $1 on a column (of 12 numbers) each time. A column pays 2 to 1, and there are 12 ways in 38 to win. Find the standard error for the gambler's net gain.

23. A gambler plays roulette 300 times, betting $1 on a column (of 12 numbers) each time. A column pays 2 to 1, and there are 12 ways in 38 to win. Find the SD of the box model that goes with this situation.

24. A gambler plays roulette 300 times, betting $1 on a column (of 12 numbers) each time. A column pays 2 to 1, and there are 12 ways in 38 to win. Find the chance that the gambler wins more than $8.50.

25. A gambler plays roulette, and makes a $1 bet on four numbers, 400 times. The bet pays 8 to 1. Find the amount of money the CASINO is expected to make.

26. A die is tossed 300 times. Find the chance that you get 50 sixes.

27. The Central Limit Theorem says that the product of the draws made at random from a box follow the normal curve, even if the contents of the box do not, as long as the number of draws is reasonably large.

28. If one tosses a pair of dice, what is the most likely sum?

29. Telephone surveys are never acceptable.

30. The Current Population Survey is a probability sample since it is a multistage cluster sample.

31. The sum of the draws from a box is 440. If the average of these draws is 2.20, how many draws were there?

32. A researcher wants to compare the English test scores of urban high school students and rural high school students. A simple random sample of 180 urban high school students is taken with a sample average of 88 and a SD of 7. An independent simple random sample of 150 rural high school students is taken with a sample average of 86 and an SD of 8. Let the population diff=pop avg for urban students - pop avg for rural students. The null hypothesis is that the population difference = 0. The alternative hypothesis is that the population difference is greater than 0. Find the sample average difference.

33. A researcher wants to compare the English test scores of urban high school students and rural high school students. A simple random sample of 180 urban high school students is taken with a sample average of 88 and a SD of 7. An independent simple random sample of 150 rural high school students is taken with a sample average of 86 and an SD of 8. Let the population diff=pop avg for urban students - pop avg for rural students. The null hypothesis is that the population difference = 0. The alternative hypothesis is that the population difference is greater than 0. Find the SE for the sample average difference.

34. A researcher wants to compare the English test scores of urban high school students and rural high school students. A simple random sample of 180 urban high school students is taken with a sample average of 88 and a SD of 7. An independent simple random sample of 150 rural high school students is taken with a sample average of 86 and an SD of 8. Let the population diff=pop avg for urban students - pop avg for rural students. The null hypothesis is that the population difference = 0. The alternative hypothesis is that the population difference is greater than 0. Find the value of the test statistic.

35. A researcher wants to compare the English test scores of urban high school students and rural high school students. A simple random sample of 180 urban high school students is taken with a sample average of 88 and a SD of 7. An independent simple random sample of 150 rural high school students is taken with a sample average of 86 and an SD of 8. Let the population diff=pop avg for urban students - pop avg for rural students. The null hypothesis is that the population difference = 0. The alternative hypothesis is that the population difference is greater than 0. Find the value of p.

36. A researcher wants to compare the English test scores of urban high school students and rural high school students. A simple random sample of 180 urban high school students is taken with a sample average of 88 and a SD of 7. An independent simple random sample of 150 rural high school students is taken with a sample average of 86 and an SD of 8. Let the population diff=pop avg for urban students - pop avg for rural students. The null hypothesis is that the population difference = 0. The alternative hypothesis is that the population difference is greater than 0. The null hypothesis is:

37. A researcher wants to compare the English test scores of urban high school students and rural high school students. A simple random sample of 180 urban high school students is taken with a sample average of 88 and a SD of 7. An independent simple random sample of 150 rural high school students is taken with a sample average of 86 and an SD of 8. Let the population diff=pop avg for urban students - pop avg for rural students. The null hypothesis is that the population difference = 0. The alternative hypothesis is that the population difference is greater than 0. True or False: The test indicates that the observed difference is due to chance.

38. A real estate office wants to make a survey in a certain town, which has 50,000 households, to determine how far the head of household has to commute to work. A simple random sample of 1,000 households is chosen, the occupants are interviewed, and it is found that on average, the heads of the sample households commuted 8.7 miles to work; the SD of the distances was 8.90 miles.(All distances are one-way; if someone isn't working, the commute distance is defined to be 0.) Find the lower confidence limit of a 99.7% confidence interval for the average commute distance of all heads of household in the town.

39. A real estate office wants to make a survey in a certain town, which has 50,000 households, to determine how far the head of household has to commute to work. A simple random sample of 1,000 households is chosen, the occupants are interviewed, and it is found that on average, the heads of the sample households commuted 8.7 miles to work; the SD of the distances was 8.90 miles.(All distances are one-way; if someone isn't working, the commute distance is defined to be 0.) Find the upper confidence limit of a 80% confidence interval for the average commute distance of all heads of household in the town.

40. A simple random sample of 400 Brand X batteries are tested. The average life of the batteries in the sample is 770 hours, and the SD of the sample is 100 hours. Compute a 95% confidence interval for the average life of all Brand X batteries.(answers are in hours)

41. A town has 20,000 registered voters, of whom 8,800 are Democrats. A survey organization takes a simple random sample of 900 registered voters. Will the bootstrap method be used in this problem?

42. A town has 82,000 voters who will vote on a school bond. Among the voters 45,100 are in favor of the school bond. A simple random sample of 200 voters is taken. Find the expected value for the sample percentage of the voters who are in favor.

43. A town has 82,000 voters who will vote on a school bond. Among the voters 45,100 are in favor of the school bond. A simple random sample of 200 voters is taken. Find the standard error for the sample percentage of voters who are in favor of the bond.

44. A town has 82,000 voters who will vote on a school bond. Among the voters 45,100 are in favor of the school bond. A simple random sample of 200 voters is taken. Find the chance that the sample percentage will be less than 48% is about:

45. A town has 82,000 voters who will vote on a school bond. Among the voters 45,100 are in favor of the school bond. A simple random sample of 200 voters is taken. Find the chance that the sample percentage will be between 50% and 62%.

46. A utility company serves 50,000 households. As part of a survey of customer attitudes, they take a simple random sample of 750 of these households. The average number of television sets in the sample households turns out to be 1.86, and the SD is 0.86. What is the observed value for the average number of television sets per household?

47. A utility company serves 50,000 households. As part of a survey of customer attitudes, they take a simple random sample of 750 of these households. The average number of television sets in the sample households turns out to be 1.86, and the SD is 0.86. Find the standard error for the sample average.

48. A person randomly picks 5 counties out of a state. He then randomly picks 2 town from each county picked. He then randomly picks 3 households from each town. He then interviews each person in the household to see what their preference is with regard to sports: Football, Baseball, Hockey, or Basketball. What type of sampling is this?

49. A test of significance does not check the design of the study.

50. A test of significance can be based on a sample of convenience.

51. For tests of significance, the alternative hypothesis corresponds to the idea that an observed difference is due to chance.

52. If we are drawing at random without replacement, and the number of draws is at least____, where the population size is 15,000, we need to use the correction factor for the calculation of SE percentage.

53. If 600 different polling firms each construct a 99% confidence interval (based on 600 different random samples) for the average age of male college students in the U.S. majoring in mathematics, how many of these intervals would you expect "on the average" to cover the true average age of such students?

54. Randomization into treatment and control helps minimize_____.

55. The civilian labor force consists of:

56. A box has three red balls and four green balls. A gambler bets $1 on red. A ball is randomly chosen. The gambler wins $1 if the ball is red, otherwise he loses $1. He will play this game 200 times. The chance that the gambler wins more than $2 is about: