STATISTICS

Sample Test (Unit 2)


Sr. Prof. Biggs

MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.
 
Find the mode(s) for the given sample data.
1)  20, 38, 46, 38, 49, 38, 49 1) ______
  A)  46
  B)  49
  C)  38
  D)  39.7

Find the midrange for the given sample data.
2)  1.5 2.5 3.0 1.2 1.3 3.8 1.8 3.3 2.3 2.9 1.8 2) ______
  A)  1.8
  B)  2.25
  C)  2.3
  D)  2.50

Find the mean of the data summarized in the given frequency distribution.
3)  The highway speeds of 100 cars are summarized in the frequency distribution below. Find the mean speed.

3) ______
  A)  61.4 mph
  B)  54.5 mph
  C)  55.8 mph
  D)  58.6 mph

Find the mode(s) for the given sample data.
4)  7.38, 7.41, 7.56, 7.38, 7.88, 7.99, 7.62 4) ______
  A)  7.38
  B)  7.41
  C)  7.56
  D)  7.603

Solve the problem.
5)  When data are summarized in a frequency distribution, the median can be found by first identifying the median class (the class that contains the median). We then assume that the values in that class are evenly distributed and we can interpolate. This process can be described by



where n is the sum of all class frequencies and m is the sum of the class frequencies that precede the median class. Use this procedure to find the median of the frequency distribution below:

5) ______
  A)  71.9
  B)  72.3
  C)  71.7
  D)  74.5

Find the mode(s) for the given sample data.
6)  99, 57, 32, 57, 29, 99 6) ______
  A)  57
  B)  62.2
  C)  99, 57
  D)  99

Find the midrange for the given sample data.
7)  The speeds (in mph) of the cars passing a certain checkpoint are measured by radar. The results are shown below. Find the midrange.
44.4 41.7 43.0 40.7 43.0
40.3 44.8 42.0 44.4 42.8
43.1 42.0 40.7 43.1 41.7
7) ______
  A)  4.50
  B)  42.8
  C)  42.55
  D)  42.35

Find the median for the given sample data.
8)  A store manager kept track of the number of newspapers sold each week over a seven-week period. The results are shown below.
95, 38, 221, 122, 258, 237, 233
Find the median number of newspapers sold.
8) ______
  A)  172 newspapers
  B)  233 newspapers
  C)  122 newspapers
  D)  221 newspapers

Find the range for the given data.
9)  Jeanne is currently taking college economics. The instructor often gives quizzes. On the past five quizzes, Jeanne got the following scores:
8 19 1 15 10
Compute the range.
9) ______
  A)  18
  B)  1
  C)  19
  D)  2

Solve the problem. Round results to the nearest hundredth.
10)  The mean height of a basketball team is 6.2 feet with a standard deviation of 0.2 feet. The team's center is 6.8 feet tall. Find the center's z score. Is his score unusual? 10) ______
  A)  3, yes
  B)  3.3, yes
  C)  2.5, no
  D)  2.55, no

Find the z-score corresponding to the given value and use the z-score to determine whether the value is unusual. Consider a score to be unusual if its z-score is less than -2.00 or greater than 2.00. Round the z-score to the nearest tenth if necessary.
11)  A body temperature of 99.7° F given that human body temperatures have a mean of 98.20° F and a standard deviation of 0.62°. 11) ______
  A)  1.5; not ususal
  B)  2.4; not unusual
  C)  -2.4; unusual
  D)  2.4; unusual

12)  A weight of 225 pounds among a population having a mean weight of 161 pounds and a standard deviation of 23.0 pounds. 12) ______
  A)  64.4; unusual
  B)  -2.8; not unusual
  C)  2.8; unusual
  D)  2.8; not unusual

Provide an appropriate response.
13)  When finding percentiles, if the locator L is not a whole number, one procedure is to interpolate so that a locator of 23.75, for example, leads to a value that is 3/4 of the way between the 23rd and 24th scores. Use this method of interpolation to find P75 for the set of test scores below.

51 54 64 68 72 74
76 84 92 94 99
13) ______
  A)  86
  B)  88
  C)  92
  D)  84

Find the range for the given data.
14)  Fred, a local mechanic, gathered the following data regarding the price, in dollars, of an oil and filter change at twelve competing service stations:
32.95 24.95 26.95 28.95
18.95 28.95 30.95 22.95
24.95 26.95 29.95 28.95
Compute the range.
14) ______
  A)  $8
  B)  $12
  C)  $14
  D)  $10

15)  A class of sixth grade students kept accurate records on the amount of time they spent playing video games during a one-week period. The times (in hours) are listed below:
23.0 15.5 9.6 24.4 15.2
30.5 24.1 16.6 15.7 14.0
Compute the range.
15) ______
  A)  7.5
  B)  20.9
  C)  9.6
  D)  15.2

Find the standard deviation for the given data. Round your answer to one more decimal place than the original data.
16)  2, 6, 15, 9, 11, 22, 1, 4, 8, 19 16) ______
  A)  2.1
  B)  7.1
  C)  6.8
  D)  6.3

Solve the problem.
17)  The heights of the adults in one town have a mean of 67.4 inches and a standard deviation of 3.4 inches. What can you conclude from Chebyshev's theorem about the percentage of adults in the town whose heights are between 60.6 and 74.2 inches? 17) ______
  A)  The percentage is at least 75%
  B)  The percentage is at most 95%
  C)  The percentage is at most 75%
  D)  The percentage is at least 95%

18)  The race speeds for the top eight cars in a 200-mile race are listed below. Use the range rule of thumb to find the standard deviation. Round results to the nearest tenth.
189.1 185.9 189.2 182.4 175.6 184.2 188.3 177.2
18) ______
  A)  1.1
  B)  3.4
  C)  7.5
  D)  6.8

Find the variance for the given data. Round your answer to one more decimal place than the original data.
19)  The normal monthly precipitation (in inches) for August is listed for 12 different U.S. cities.
3.5 1.6 2.4 3.7 4.1 3.9
1.0 3.6 4.2 3.4 3.7 2.2
Compute the variance.
19) ______
  A)  0.94
  B)  1.00
  C)  1.05
  D)  1.09

Find the standard deviation of the data summarized in the given frequency distribution.
20)  The test scores of 40 students are summarized in the frequency distribution below. Find the standard deviation.

20) ______
  A)  s = 14.4
  B)  s = 13
  C)  s = 12.3
  D)  s = 13.7