Course 1 Unit 1

Lesson 2 Investigation 2-Producing Plots with Technology

Page 19

1.  a. Teaching Master 14a&b shows you how to use your TI-83 to produce the histogram. Put this teaching master in your toolkit. Carefully sketch the histogram at the right.

b.  As you TRACE the bars, complete the table below:

Min / Max / n
Bar 1
Bar 2
Bar 3
Bar 4
Bar 5

If a value occurs on the edge of the bar, is it counted in the bar on the left or the bar on the right?

c.  Describe the overall shape of the distribution of ratings. When describing this overall shape, determine if the shape is approximately normal, skewed to the left, or skewed to the right.

d. What is the most common rating? How can you tell from the histogram?

e.  Change the “Xscl” value to 2. What does this do to the histogram? Why? Does it change the basic shape of the histogram?

f.  Experiment with other widths for each bar. Which value seems to be the best for displaying these data?

2. Divide the remaining ten cars listed on page 15 among your group.

a. Each group member should draw 2 to 3 histograms below. Be sure to label your histogram with the name of the car.

b. Which cars have symmetrical ratings?

Which cars have a distribution that is skewed? What does this tell you about the car’s ratings?

Which distributions are spread out the most?

Which distributions are spread out the least?

What does it mean if the ratings for a car have a large spread?

c. For which car(s) is the distribution of ratings centered at the lowest value?

d.  Based on the histograms, select the top four cars you would consider buying. How did the plots help you make your choice?

3.  As a group, examine the data in the table. What information do you find surprising or interesting?

4.  Many people order chicken in fast food restaurants because they believe it will have less fat than a hamburger. Does it appear from the table that they are right or wrong? Explain your response.

5. Consider the data on the total number of calories for the fast foods list.

a. Make the histogram on your TI-83 graphing calculator. Use the values Xmin = 0, Xmax = 1100, Ymin= -2, Ymax = 10, and Yscl=1. You do not need to draw the histogram here however, determine the value of Xscl that seems to give a good picture of the distribution. What Xscl value did you use?

b. Why isn’t 137 the best value to use for Xmin?

c. Describe the pattern of data that you can see from the histogram. Consider the usual features such as the spread, approximate location of the center, symmetry or skewness, gaps, and any unusual values.

6. Now consider the data on the amount of cholesterol in the listed fast foods.

a. Make a histogram of the values. Use Ymin= -4, Ymax=10, and Yscl=2. Experiment with your own values of Xmin, Xmax, and Xscl.

State your values for Xmin, Xmax, and Xscl.

Xmin = ______Xmax = ______Xscl = ______

b. Describe the histogram of the amount of cholesterol in fast foods.

c. Change the maximum y value to 5. Is this a good choice? Why or why not?

Checkpoint

a.  What does the shape of a distribution tell you about the data?

b.  If you are producing a histogram with your calculator, how will you decide on the best choice for the bars?

c.  How will you decide on a reasonable value for the maximum y value?

Course 1 Unit 1 Lesson 2 Investigation 2 Page 5 of 5