Econ 206/Test 1 (Version A) Write your name and version on the scantron (-2 if not)
Suppose that the monthly water bills for a residence were: $100, $80, $120, $110, $90
1. The median monthly expense is
a. $100 b. $90
c. $80 d. $120
2. The standard deviation of monthly expense is about
a. $5.6 b. $10.0
c. $12.7 d. $15.8
3. The sum of the squared deviations from the mean, (Xi - )2, in the data above is
a. 125 b. 400
c. 1000 d. 2500
4. The range for this data set is
a. $10 b. $100
c. $50 d. $40
5. The data
a. reflect random sampling
b. have no deviation from the mean
c. are qualitative
d. have no skew
6. Which of the following statements is correct?
a. If data is bimodal, it should be split into two groups before being examined further
b. quantitative is more flexible than qualitative data
c. pie charts are a valuable graphic when displaying quantitative data
d. convenience samples are equivalent to random samples
7. Consider a variable with four observations: 2, 4, 6, 8. Using all of the data, (Xi )2 would equal:
a. 18 b. 20
c. 120 d. 400
8. Consider a set of four scores on a ten-point quiz: 5, 7, 8, and 9. Suppose that a grading mistake was found, and the score of 9 was changed to a 10. As a result,
a. the standard deviation would increase
b. the median would increase
c. the skewness would decrease
d. all of the above
The following table provides descriptive statistics on job experience (in months) for 474 employees.
experience / Mean / 176.9 / 4.8
95% Confidence Interval for Mean / Lower Bound / 167.4
Upper Bound / 186.4
5% Trimmed Mean / 166.1
Median / 140.0
Variance / 11045.7
Std. Deviation / 105.0
Minimum / 65.0
Maximum / 554.0
Range / 489.0
Interquartile Range / 122.2
Skewness / 1.4 / .1
Kurtosis / 1.6 / .2
9. In SPSS, the preceding Table could be produced by
a. the “Explore” command b. the “Transform” command
c. the “Compute” command d. the “Statistics” command
10. Based on the statistics in the preceding table,
a. half of the workers had more than 176 months of experience
b. there are more extreme values than in a bell-shaped data set
c. the difference between monthly experience and mean experience is about 489 months on average
d. none of the above
11. The number that summarizes the degree of symmetry (or asymmetry) in the data set is
a. 1.4 b. 1.6
c. 105.0 d. none of the above
12. The standardized value for a worker with 6 years (72 months) of experience would be
a. 0.5 b. 2.5
c. –0.5 d. –1.0
13. Based on the characteristics of the experience data, it would be accurate to conclude that
a. 99.7% of the incomes would be within 315 months of 176
b. 95% of the incomes would be within 210 months of 176
c. 68% of the incomes would be within 105 months of 176
d. none of the above
14. A key feature of mini-Assignment 2 focused on producing
a. a histogram of Dow Jones Index b. descriptive statistics for S&P 500 values
c. a bar chart of CPI values d. descriptive statistics on GDP
15. Which of the following is regarding sIn the 1971 lottery for military draft dates, all 365 birth dates for a given year were placed into a large “hopper,” spun several times, and then individual dates were blindly drawn out one at a time. This reflects which kind of sampling?
a. random b. stratified random
c. cluster d. systematic
16. Suppose you were given a variable where the mean is 50, the maximum and minimum are 25 and 75, and the other data values are fairly even spread out between the maximum and the minimum. Based on the information, the standard deviation for this variable is likely to be
a. between 1 and 2 b. between 5 and 10
c. between 10 and 20 d. between 25 and 50
17. The data in the figure above
a. would have 68% of its values between 1 and –1 standard deviations
b. should be split into two groups before being examined with statistics
c. will have a kurtosis coefficient near zero
d. will have a mean much larger than its median
18. In one class, the vast majority of test scores usually fall between 70 and 90 with a few scores sometimes falling off well below 50. What is the most likely shape of the of class scores with these conditions in mind?
a. positively skewed b. negatively skewed
c. bell-shaped d. pie-shaped
19. Suppose that the standard deviation for an exam turns out to be very small. Which of the following is true?
a. The class received very similar scores
b. The class received very dissimilar scores
c. The class is negatively skewed
d. The entire class received very high scores.
bush % Stem-and-Leaf Plot
Frequency Stem & Leaf
33.00 Extremes (=<26)
20.00 2 . 8&
72.00 3 . 02234&
123.00 3 . 55667788999
212.00 4 . 000111222333334444
374.00 4 . 55555666667777777888888899999999
504.00 5 . 000000011111111222222222333333334444444444
520.00 5 . 555555555666666667777777778888888899999999
490.00 6 . 0000000011111111122222222333333334444444
334.00 6 . 5555555666666777778888899999
220.00 7 . 000001111222333444
135.00 7 . 55566677889
56.00 8 . 01123&
12.00 8 . 5&
6.00 Extremes (>=89)
Stem width: 10.00
Each leaf: 12 case(s)
& denotes fractional leaves.
The graphic above for displays the percent vote for Bush in the 2000 election for all U.S. counties.
20. This graphic indicates that
a. 504 counties had 50 to 54 percent
b. 37.4 percent of counties had 40-something percent
c. all of the counties had less than 89 percent
d. none of the above
21. To evaluate how the “spread” or variability of a particular observation in a data set, you would use
a. skewness coefficient b. kurtosis coefficient
c. standard deviation d. standardized values
22. Suppose that we found that the mean of student distanced traveled to campus is
70 miles and the standard deviation is 10 miles. Then, a student who travels 90 miles will have
z-value of
a. 20 b. 2.0
c. –1.0 d. none of the above
23. Suppose that we collected data on age (measured in years) for a sample of 100 Burger King customers on October 1. This is an example of
a. qualitative data b. cross-sectional data
c. experimental data d. longitudinal data
24. If we code males into our data file as 0s and females as 1s, we have
a. experimental data b. quantitative data
c. random data d. none of the above
25. Suppose that 10 females and 10 males are selected for a sample by blindly picking names out of a hopper for all females and a separate hopper for all males. This is an example of
a. cluster sampling b. stratified random sampling
c. simple random sampling d. systematic sampling
26. If we sample by dividing a population into two groups, such as men and women, placing names into a hopper, mixing the names well in the hopper, and then selecting 10 names, we use
a. a stratified random sample b. a self-selected sample
c. a systematic sample d. a convenience sampled
27. A sampling method that provides all elements of the population the same chance of selection
a. is an unbiased method b. contains no error
c. is a systematic sample d. all of the above
28. If you analyze a highly skewed data set,
a. split the data into two groups before further examination
b. use the interquartile range rather than the standard deviation to measure spread
c. the median is a better measure of the center than the mean
d. calculate the mean divided by the interquartile range
29. Which formula is correct for computing percent change in monthly S&P 500 values?
a. current month – prior month
b. (current month – prior month)*100
c. (prior month/current month)*100
d. ((current month – prior month)/prior month)*100
30. Suppose you were given the following information on batting averages:
10th percentile = 230 60th percentile = 282
20th percentile = 242 75th percentile = 290
25th percentile = 249 80th percentile = 296
40th percentile = 263 90th percentile = 304
50th percentile = 275 100th percentile = 366
A boxplot constructed from this data, the “box” would begin and end at
a. 230, 304 b. 242, 296
c. 249, 290 d. none of the above
N / Minimum / Maximum / Mean1 if popden>1000 per sq mi / 3138 / .00 / 1.00 / .0402
Valid N (listwise) / 3138
31. The table above represents statistical results for U.S. counties. The variable is equal to 0 if the population density of a county is less than 1000 people per square mile and equal to 1 if the population is greater than 1000 people per square mile. Pick the correct answer
a. the variable is qualitative
b. the mean reflects the proportion of counties labeled as “1”
c. 4.02 percent of counties contain more than 1000 people per square mile
d. all of the above
The graphic above represents an X-bar chart for daily measurements of “peak-flow” of a person’s lungs.
32. Based on this data, it is reasonable to conclude that
a. the standard deviation of the series is 30
b. the series has an abnormal amount of variation
c. the series contains a downward trend
d. the data roughly conforms to the empirical rule
33. Based on the chart above
a. aggressive intervention should have been initiated for the measurements below 590
b. aggressive intervention should have been initiated for measurements below 580
c. aggressive intervention should have been initiated for all values below 600
d. none of the above
34. Put “A” for your answer
Correct Answers Version A:
1a, 2d, 3c, 4d, 5d, 6a, 7c, 8a, 9a or d, 10b, 11a, 12d, 13d, 14b, 15a, 16c, 17d, 18b, 19a, 20a,
21c or d, 22b, 23b, 24d, 25b, 26a, 27a, 28c, 29d, 30c, 31d, 32d, 33d, 34a