ECON 6100
Dr. Tufte
Statistics Quiz
These will be scored, but the grade will not count in the conventional sense. Your quiz will be scored like an SAT: you will get n points for a correct answer, 0 for a blank answer, and you will lose 1 point for an incorrect answer, where n is the number of choices for that question. You may take this quiz up to 6 times. If you do not achieve a perfect score after 6 attempts, I will reduce your final letter grade by 1/3 (e.g., from an A- to a B+).
Questions 1 through 5 have no correct answer, and will be tabulated but not scored.
1) Describe yourself
A) I understand statistics currently
B) I understood statistics at one time, but I need a refresher
C) I didn’t understand statistics, but I got a grade that was probably better than I deserved
D) I never understood statistics
2) Describe your situation
A) I own a statistics book
B) I have access to a statistics book (other than from the library)
C) I do not have a statistics book I could refer to
3) Describe your exposure to statistics
A) I never had statistics
B) 1 semester
C) 2 semesters
D) More than 2 semesters
4) To the best of my knowledge, my exposure to statistics stopped around this topic
A) Averages and standard deviations
B) Probability distributions
C) Interval estimation and hypothesis testing
D) Regression analysis
5) My formal statistical education is best described as
A) Taught by mathematics professors, and I was a mathematics major
B) Taught by mathematics professors, and I was not a mathematics major
C) Taught by professors in my major
Questions 6 through 40 will be scored. The scoring for each question is that each correct answer is worth one less than the number of choices for that question, while each incorrect answer loses one point. Astute readers will note that this means that random guessing has no expected benefit or loss, but that it worthwhile to guess if you can eliminate one or more of the choices (like an SAT).
6) Data that cannot be usefully ordered (such as eye color) is called
A) Interval
B) Nominal
C) Ordinal
D) Ratio
7) The data from student evaluations (in which, say, a 5 is better than a 4, which in turn is better than a 3) is called
A) Interval
B) Nominal
C) Ordinal
D) Ratio
8) The amount of currency you have in your possession right now is an example of which type of data
A) Interval
B) Nominal
C) Ordinal
D) Ratio
9) Which do you estimate?
A) Parameters
B) Statistics
C) Both A and B
D) Neither A or B
10) If you want to check if a distribution is approximately symmetric, you should use
A) A histogram
B) A stem and leaf diagram
C) Either A or B
D) Neither A or B
11) If you want to determine the median of a data set, you should examine the
A) A histogram
B) A stem and leaf diagram
C) Either A or B
D) Neither A or B
12) What is the mode for hourly wages in this country?
A) The minimum wage
B) Some other numerical value
13) Which is higher, the mean or median price of a home in Cedar City?
A) Mean
B) Median
14) If you were trying to decide on a method for forecasting a score in an upcoming football game, which of the following would be false?
A) The shortcoming of using the mean of past scores is that you may get a numerical value that can’t possibly be scored
B) The shortcoming of using the median of past scores is that you may get a numerical value that can’t possibly be scored
C) The shortcoming of using the mode of past scores is that you may get a numerical value that can’t possibly be scored
15) Deviations from the mean of a sample should
A) Sum to zero
B) Sum to more than zero
16) Squared deviations from the mean of a sample should
A) Sum to zero
B) Sum to more than zero
17) When people working in finance say that a portfolio’s risk can be reduced by diversification, what statistical measure are they referring to by risk?
A) Interquartile range
B) Variance
C) Variation
18) What is the expected value if you role a single die?
A) 3
B) 3.5
C) 4
19) If you flip a coin 7 times, and write down H for heads and T for tails, how many possible sequences of those two letters are there?
A) 2
B) 7
C) 14
D) 256
E) None of the above
20) The color a compliant browser applies to a web page as coded in HTML depends on the saturation (i.e., darkness of hue) of red, blue, and green. There are 6 possible saturations for each color. How many possible colors can the browser display?
A) 6
B) 18
C) 27
D) 216
E) 5832
21) Suppose that you are asked by your boss to figure out how many possible three person committees can be formed from the people in your six person department. The appropriate distribution to use is the
A) Binomial
B) Hypergeometric
C) Normal
D) Uniform
22) Suppose that you are assigned by the police department to determine how likely it is that a patrol car will have to wait along a highway for an hour or more before a speeder drives by. The appropriate distribution to use is the
A) Binomial
B) Exponential
C) Negative Binomial
D) Normal
23) Suppose you are assigned by the athletic department to determine how many wins our basketball team will earn over the rest of the season, assuming that they continue to win at the pace they’ve shown so far. The appropriate distribution to use is the
A) Binomial
B) Geometric
C) Hypergeometric
D) Negative binomial
24) If you are trying to determine if you have enough ambulances on hand for a football game in which there is on average 1 injury for every 5,000 people attending, you should use which distribution:
A) Binomial
B) Normal
C) Poisson
D) Uniform
Answer questions 25 through 30 based on the following. I first read about this in Best of the Web Today, a weblog at OpinionJournal.Com, however, the article was genuinely in the Salt Lake Tribune (however, their link no longer works).
The menu at
the Coffee Garden at 900 East and
900 South in Salt Lake City has included a scrumptious selection of quiche for about
10 years.
The recipe calls for four fresh eggs for each quiche.
A Salt Lake County Health Department inspector paid a visit recently and
pointed out that research by the Food and Drug Administration indicates that
one in four eggs carries salmonella bacterium, so restaurants should never use
more than three eggs when preparing quiche.
The manager on duty wondered aloud if simply throwing out three eggs from each
dozen and using the remaining nine in four-egg-quiches would serve the same
purpose.
The inspector wasn't sure, but she said she would research it.
25) In the third paragraph, the implication is that the expected value of the number of salmonella contaminated eggs in a 4 egg quiche is
A) 1
B) 3
C) 4
26) The probability that a 4 egg quiche is free of salmonella is
A) 0
B) Between 0 and 1
C) 1
27) Making the quiche with 3 eggs rather than 4
A) Decreases the expected value of the number of salmonella contaminated eggs
B) Does not change the expected value of the number of salmonella contaminated eggs
C) Increases the expected value of the number of salmonella contaminated eggs
28) Making the quiche with 3 eggs rather than 4
A) Decreases the probability that the quiche is contaminated with salmonella
B) Does not change the probability that the quiche is contaminated with salmonella
C) Increases the probability that the quiche is contaminated with salmonella
29) Throwing out 3 eggs from each dozen, and then making 4 eggs quiches from the remaining 9 eggs
A) Decreases the expected value of the number of salmonella contaminated eggs
B) Does not change the expected value of the number of salmonella contaminated eggs
C) Increases the expected value of the number of salmonella contaminated eggs
30) Throwing out 3 eggs from each dozen, and then making 4 eggs quiches from the remaining 9 eggs
A) Decreases the probability that the quiche is contaminated with salmonella
B) Does not change the probability that the quiche is contaminated with salmonella
C) Increases the probability that the quiche is contaminated with salmonella
31) The point of the central limit theorem is that it says that
A) In a sample, many sample statistics are approximately normally distributed
B) In a sample, many sample statistics are normally distributed
C) In a large enough sample, many sample statistics are approximately normally distributed
D) In a large enough sample, many sample statistics are normally distributed
32) What is the probability that your body temperature is exactly 98.6 degrees Fahrenheit?
A) Zero
B) Greater than zero but less than one
C) One
33) Generally speaking, our confidence is higher that your body temperature is between 97 and 100 degrees rather than 98 and 99 degrees.
A) True
B) False
34) Generally speaking, a larger sample size implies that
A) Your statistical statements can be made with higher confidence
B) Your interval estimates can be narrower
C) Both A and B
D) Neither A or B
35) The legal system in this country, in which the defendant is presumed innocent until proven guilty, tends to bias the system towards what sort of error
A) Type I
B) Type II
36) If a hypothesis is rejected by a statistical test, it must be false
A) True
B) False
37) The standard is that statistical tests of true hypotheses should come to the wrong conclusion
A) Never
B) 1% of the time
C) 5% of the time
D) More than 5% of the time
38) The standard is that statistical tests of false hypotheses should come to the right conclusion
A) Never
B) 1% of the time
C) 5% of the time
D) More than 5% of the time, and ideally much more
39) The phrase “six sigma” that is popular in the quality control literature within management is based upon what statistical concept
A) The Central Limit Theorem
B) Standard deviations
C) Approximate normality
D) All of the above
40) The t distribution was originally studied by quality controllers in what industry
A) Brewing
B) Railroads