Chapter 2

An example of manipulating a graphical display to distort reality is ___________.

stretching the axes Starting the axes at zero is the appropriate method of graphical display, as is making the bars in a histogram equal widths.

A flaw possessed by a population or sample unit is ___________.

a defect

When grouping a large sample of measurements into classes, the ______________ is a better tool than the ___________.

histogram, stem-and-leaf display A box plot does not easily group measurements into classes; a scatter plot is for looking at the relationship between two variables.

A CFO is looking at what percentage of a company's resources are spent on computing. He samples companies in the pharmaceutical industry and develops the following stem-and-leaf graph. 5 | 269 6 | 255568999 7 | 11224557789 8 | 001222458 9 | 02455679 10 | 1556 11 | 137 12 | 13 | 255 If you were creating a frequency histogram using these data, how many classes would you create?

6 There are 50 data measurements. 2^k, where k = number of classes and 2^k is the closest value larger than 50. 2^6 = 64.

A histogram that tails out toward smaller values is ___________.

Skewed to the left

A Stem-and-leaf display is best used to ___________.

display the shape of the distribution

The following data consist of the revenue growth rates (in percent) for a group of 20 firms. 27, 60, 79, 58, 87, 76, 61, 99, 37, 23, 95, 68, 60, 35, 98, 42, 65, 92, 56, 89 Construct a stem-and-leaf display for the above data.

Stem Unit - 10 Leaf Unit - 1 Frequency Stem Leaf 2 2 3 7 2 3 5 7 1 4 2 2 5 6 8 5 6 0 0 1 5 8 2 7 6 9 2 8 7 9 4 9 2 5 8 9 total 20

A multiple choice question on an exam has four possible responses—(a), (b), (c), and (d). When 340 students take the exam, 204 give response (a), 34 give response (b), 68 give response (c), and 34 give response (d). Consider constructing a pie chart for the exam question responses. a) How many degrees (out of 360) would be assigned to the "pie slice" for response (a)? b) How many degrees would be assigned to the "pie slice" for response (b)?

a) 216 degrees 204/340 = x/360 b) 36 degrees 34/340 = x/360

The following is a partial relative frequency distribution of consumer preferences for four products—W, X, Y, and Z. W - 0.28 X - Y - 0.3 Z - 0.15 (a) Find the relative frequency for product X. (b) If 400 consumers were surveyed, give the frequency distribution for these data. (d) If we wish to depict these data using a pie chart, find how many degrees (out of 360) should be assigned to each of products W, X, Y, and Z.

(a) 0.27 1-(0.28+0.3+0.15)=0.27 (b) W - 112 X - 108 Y - 120 Z - 60 0.28*400=112 (c) W - 100.8 X - 97.2 Y - 108 Z - 54 100.8/400 = x/360

As a general rule, when creating a stem-and-leaf display, there should be ______ stem values.

between 5 and 20

A CFO is looking at what percentage of a company's resources are spent on computing. He samples companies in the pharmaceutical industry and develops the following stem-and-leaf graph. 5 | 269 6 | 255568999 7 | 11224557789 8 | 001222458 9 | 02455679 10 | 1556 11 | 137 12 | 13 | 255 What is the approximate shape of the distribution of the data?

skewed to the right

In an article in Quality Progress, Barbara A. Cleary reports on improvements made in a software supplier's responses to customer calls. In this article, the author states: In an effort to improve its response time for these important customer-support calls, an inbound telephone inquiry team was formed at PQ Systems, Inc., a software and training organization in Dayton, Ohio. The team found that 88 percent of the customers' calls were already being answered immediately by the technical support group, but those who had to be called back had to wait an average of 56.6 minutes. No customer complaints had been registered, but the team believed that this response rate could be improved. As part of its improvement process, the company studied the disposition of complete and incomplete calls to its technical support analysts. A call is considered complete if the customer's problem has been resolved; otherwise, the call is incomplete. The following Figure 2.6 shows a Pareto chart analysis for the incomplete customer calls. Get more data - 27.13% More investigation - 22.16% Callback - 18.36% Development assistance - 13.08% Administrative help - 11.06% New problem - 8.21% (a) What percentage of incomplete calls required "more investigation" by the analyst or "administrative help"? (b) What percentage of incomplete calls actually presented a "new problem"?

(a) 33.22% 22.16%+11.06%=33.22% (b) 8.21%

A CFO is looking at what percentage of a company's resources are spent on computing. He samples companies in the pharmaceutical industry and develops the following stem-and-leaf graph. 5 | 269 6 | 255568999 7 | 11224557789 8 | 001222458 9 | 02455679 10 | 1556 11 | 137 12 | 13 | 255 What would be the class length used in creating a frequency histogram?

1.4 There are 50 data measurements. 2^k, where k = number of classes and 2^k is the closest value larger than 50. 2^6 = 64, so 6 classes. Class length = (Max value − Min value)/6 = (13.5 − 5.2)/6. Length = 1.38, rounded to 1.4.

The number of items rejected daily by a manufacturer because of defects for the last 30 days are: 20, 21, 8, 17, 22, 19, 18, 19, 14, 17, 11, 6, 21, 25, 4, 19, 9, 12, 16, 16, 10, 28, 24, 6, 21, 20, 25, 5, 17, 8 How many classes should be used in constructing a histogram?

5 Number of classes = k, where 2^k > 30. So k = 5.

A CFO is looking at what percentage of a company's resources are spent on computing. He samples companies in the pharmaceutical industry and develops the following stem-and-leaf graph. 5 | 269 6 | 255568999 7 | 11224557789 8 | 001222458 9 | 02455679 10 | 1556 11 | 137 12 | 13 | 255 What would be the first class interval for the frequency histogram?

5-2 - 6.5 There are 50 data measurements. 2^k, where k = number of classes and 2^k is the closest value larger than 50. 2^6 = 64, so 6 classes. Class length = (Max value − Min value)/6 = (13.5 − 5.2)/6. Length = 1.38, rounded to 1.4. The boundary for the first non-overlapping interval is the smallest measurement and the sum of the first measurement and the length (5.2 + 1.38 = 6.58). So the first interval will contain the values 5.2 − 6.5. this is fcking retarded tho cuz 5.2+1.4=6.6

A CFO is looking at what percentage of a company's resources are spent on computing. He samples companies in the pharmaceutical industry and develops the following stem-and-leaf graph. 5 | 269 6 | 255568999 7 | 11224557789 8 | 001222458 9 | 02455679 10 | 1556 11 | 137 12 | 13 | 255 What is the smallest percentage spent on R&D?

5.2

If there are 130 values in a data set, how many classes should be created for a frequency histogram?

8 2^k, where k = number of classes and 2^k is the closest value larger than 130. 2^7 = 128; 2^8 = 256.

A multiple choice question on an exam has four possible responses—(A), (B), (C), and (D). When 480 students take the exam, 192 give response (A), 144 give response (B), 48 give response (C), and 96 give response (D). Write out the frequency distribution, relative frequency distribution, and percent frequency distribution for these responses.

Category Frequency Relative Percentage /Class Frequency Frequency A 192 0.4 40% B 144 0.3 30% C 48 0.1 10% D 96 0.2 20%

The general term for a graphical display of categorical data made up of vertical or horizontal bars is called a(n) ___________.

bar chart An ogive plot is based on quantitative data, a Pareto chart is a specialized bar chart, and a pie chart is a circular graphical display.

A _____________ displays the frequency of each group with qualitative data and a _____________ displays the frequency of each group with quantitative data.

bar chart, histogram The histogram and stem-and-leaf are used to graphically display quantitative data; a scatter plot is used for displaying the relationship between two variables.

A graphical portrayal of a quantitative data set that divides the data into classes and gives the frequency of each class is a(n) ___________.

histogram Pareto and bar charts are used for qualitative data, a dot plot displays individual data points, and an ogive plot is a curved display of the cumulative distribution of the data.

A company collected the ages from a random sample of its middle managers, with the resulting frequency distribution shown below. Class Interval Frequency 20 to <25 8 25 to <30 6 30 to <35 5 35 to <40 12 40 to <45 15 45 to <50 7 What would be the approximate shape of the relative frequency histogram?

skewed to the left The majority of data lie to the right side of the distribution; the tail of the smaller number of measurements extends to the left, so the graph is skewed with a tail to the left.