Stats HWRK Ch. 2

Determine whether the following statement is true or false. The shape of the distribution shown is best classified as skewed left.

False

Determine whether the following statement is true or false. The shape of the distribution shown is best classified as skewed left. A histogram with a horizontal axis labeled from 0 to 30 in increments of 3 and an unlabeled vertical axis contains 10 vertical bars. Assuming the rightmost bar has height 1, the bars have approximate heights as follows, where horizontal ranges are listed first and heights are listed second: 0 to 3, 6; 3 to 6, 10; 6 to 9, 13; 9 to 12, 9; 12 to 15, 6; 15 to 18, 5; 18 to 21, 2.5; 21 to 24, 2; 24 to 27, 1; 27 to 30, 1. Choose the correct answer below.

False

For ages of students in a public school​, state whether you would expect a histogram of the data to be​ bell-shaped, uniform, skewed​ left, or skewed right. Choose the correct answer below.

Uniform

A newspaper article claimed that the afternoon hours were the worst in terms of robberies and provided the graph to the right in support of this claim. Explain how this graph is misleading.

Not all of the time intervals are the same size. Redistributing the time interval so they are all the same size may lead to a different shape.

The safety manager at Bumbler Enterprises provides the graph shown on the right to the plant manager and claims that the rate of worker injuries has been reduced by 50​% over a​ 12-year period. Does the graph support his​ claim? Explain.

The graph does not support his claim. The vertical scale does not start at 0 which distorts the percent of change.

In a relative frequency​ distribution, what should the relative frequencies add up​ to? Select the correct choice​ and, if​ necessary, fill in the answer box to complete your choice.

The relative frequencies add up to 1.

The following frequency histogram represents the IQ scores of a random sample of​ seventh-grade students. IQs are measured to the nearest whole number. The frequency of each class is labeled above each rectangle. Use the histogram to answers parts​ (a) through​ (g). ​(a) How many students were​ sampled? ​(b) Determine the class width. ​(c) Identify the classes and their frequencies. Choose the correct answer below. ​(d) Which class has the highest​ frequency? ​(e) Which class has the lowest​ frequency? ​(f) What percent of students had an IQ of at least 130?

A. 200 students B. The class width is 10 C.60-69, 2​; 70-79, 3​;80-89, 11​; 90-99, 54​;100-109, 46​;110-119, 41​;120-129, 30;130-139, 8​;140-149, 4​; 150-159, 1 D. 90-99 E. 150-159 F. 6.5% G.​No, because there are no​ bars, or​ frequencies, greater than an IQ of 160.

The figures to the right represent the number of bakeries in two towns. ​(a) How are the figures misleading? ​(b) What could be done to improve the​ graphic?

A. It looks like Warm Springs has significantly more bakeries than Denton. B. The Denton figure should be 70% as large as the Warm Springs figure.

An airline offers discounted flights from Atlanta to five American cities. Below is a frequency distribution of the number of tickets purchased for each location based on a random sample of purchased tickets. Complete parts ​(a) through ​(f). Response / Frequency Las Vegas 1269 Orlando 1265 New York 1120 Chicago 567 San Diego 672 ​(a) Construct a relative frequency distribution of the data. ​(b) What proportion of the tickets were for New​ York? ​(c) Construct a frequency bar graph. Choose the correct answer below. ​(d) Construct a relative frequency bar graph. Choose the correct answer below. ​(e) Construct a pie chart. Choose the correct answer below. ​(f) A local news broadcast reported that 13.7​% of tickets purchased from the airline are for flights to San Diego. What is wrong with this​ statement?

A. Response / Rel.Frequency Las Vegas 0.259 Orlando 0.259 New York 0.229 Chicago 0.116 San Diego 0.137 B. 0.229 C. a D. b E. a F.​No level of confidence is provided along with the estimate.

A national survey asked​ people, "How often do you eat out for​ dinner, instead of at​ home?" The frequencies were as follows. Complete parts ​(a) through ​(g). Response / Frequency Never 433 Rarely 351 Sometimes 979 Most of the time 237 Always 43 ​(a) Construct a relative frequency distribution of the data. ​(b) What percentage of respondents answered​ "Always"? ​(c) What percentage of respondents answered​ "Never" or​ "Rarely"? ​(d) Construct a frequency bar graph. Choose the correct answer below. ​(e) Construct a relative frequency bar graph. Choose the correct answer below. ​(f) Construct a pie chart. Choose the correct answer below. (g) Suppose a person claims​ that, "2.1​% of all people in the nation always eat​ out." Is this a descriptive or inferential​ statement?

A. Response / Relative Frequency Never 0.212 Rarely 0.172 Sometimes 0.479 Most of the time 0.116 Always 0.021 B. 2.1% C. 38.4% D. c E. a F. d G. inferential

The following graph shows the median earnings for females from 2005 to 2009 in constant 2009 dollars. Complete parts ​(a) and​ (b) below. ​(a) How is the bar graph​ misleading? What does the graph seem to​ convey? ​(b) Redraw the graph so that it is not misleading. Choose the correct graph below. What does the new graph seem to​ convey?

A. The vertical axis starts at​ 34,500 instead of 0. This tends to indicate that the median earnings for females changed at a faster rate than it actually did. B. c, This graph indicates that median earnings for females have remained fairly constant over the given time period.