Stats Chapter 2 Online HW

8 September 2022
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question
Does the frequency distribution appear to have a normal‚Äč distribution? Explain. Temperature_ (F) Frequency 35-39 1 40-44 3 45-49 10 50-54 12 55-59 10 60-64 2 65-69 1
answer
Yes, because the frequencies start‚Äč low, proceed to one or two high‚Äč frequencies, then decrease to a low‚Äč frequency, and the distribution is approximately symmetric.
question
Does the result appear to have a normal‚Äč distribution? Why or why‚Äč not?
answer
Yes, because the frequencies start low comma reach a maximum comma then become low again, and are roughly symmetric about the maximum frequency.
question
________are sample values that lie very far away from the majority of the other sample values.
answer
outliers
question
Class width is found by‚Äč _______.
answer
subtracting a lower class limit from the next consecutive lower class limit
question
The histogram to the right represents the weights‚Äč (in pounds) of members of a certain‚Äč high-school programming team. How many team members are included in the‚Äč histogram?
answer
The histogram represents 18 programming team members. (the x-axis shows weight in pounds, but the y-axis is frequency)(you would count the frequency from each bar in the histogram to get total members).
question
The graph to the right compares teaching salaries of women and men at private colleges and universities. What impression does the graph‚Äč create? Does the graph depict the data‚Äč fairly? If‚Äč not, construct a graph that depicts the data fairly. a.What impression does the graph‚Äč create? b.Does the graph depict the data‚Äč fairly?
answer
a. The graph creates the impression that men have salaries that are more than twice the salaries of women. b. ‚ÄčNo, because the vertical scale does not start at zero.
question
The graph to the right uses cylinders to represent barrels of oil consumed by two countries. Does the graph distort the data or does it depict the data‚Äč fairly? Why or why‚Äč not? If the graph distorts the‚Äč data, construct a graph that depicts the data fairly.
answer
Yes, because the graph incorrectly uses objects of volume to represent the data.
question
The graph to the right shows the braking distances for different cars measured under the same conditions. Describe the ways in which this graph might be deceptive. How much greater is the braking distance of Car A than the braking distance of Car‚Äč C? Draw the graph in a way that depicts the data more fairly. a. In what way might the graph be‚Äč deceptive? b. How much greater is the braking distance of Car A than the braking distance of Car‚Äč C?
answer
a. By starting the horizontal axis at‚Äč 100, the graph cuts off portions of the bars. b. The braking distance of Car A is about 40‚Äč% greater than the braking distance of Car C.
question
Use the pulse rates‚Äč (beats per‚Äč minute) of males in the accompanying data set to construct a frequency distribution. Begin with a lower class limit of 40 and use a class width of 10. Do the pulse rates of males appear to have a normal‚Äč distribution? b.) Do the pulse rates of males appear to have a normal‚Äč distribution?
answer
a.) Pulse Rate Frequency 40‚Äč-49 2 50‚Äč-59 21 60‚Äč-69 55 70‚Äč-79 41 80‚Äč-89 27 90‚Äč-99 5 100‚Äč-109 2 b.)The pulse rates of males appear to have a normal distribution because the frequencies start low, increase, and then decrease; and are roughly symmetric.
question
Identify the class width and class midpoints. Height (inches) Frequency 59.0-61.9 4 62.0-64.9 25 65.0-67.9 9 68.0-70.9 1 71.0-73.9 0 74.0-76.9 0 77.0-79.9 0 80.0-82.9 0 83.0-85.9 0 86.0-88.9 1
answer
a). What is the class‚Äč width? 3 b.)What are the class‚Äč midpoints? 60.45, 63.45‚Äč, 66.45‚Äč, 69.45 ‚Äč,72.45 ‚Äč,75.45‚Äč, 78.45‚Äč, 81.45‚Äč,84.45, 87.45
question
The table below shows the magnitudes of the earthquakes that have occurred in the past 10 years. magnitude Frequency 5.0-5.9 6 6.0-6.9 6 7.0-7.9 13 8.0-8.9 4 9.0-9.9 2 Use the frequency distribution to construct a histogram. Using a loose interpretation of the requirements for a normal‚Äč distribution, does the histogram appear to depict data that have a normal‚Äč distribution? Why or why‚Äč not?
answer
a.) Does the histogram appear to depict data that have a normal‚Äč distribution? The histogram appears to roughly approximate a normal distribution. The frequencies generally increase to a maximum and then‚Äč decrease, and the histogram is symmetric.