eQuizShow

Chapter 7 Math

Mean Absolute Deviation

Question: What is the definition of mean absolute deviation?
Answer: Mean absolute deviation describes the average distance from the mean for the numbers in the data set.

Question: What is the first thing that you should do when calculating mean absolute deviation?
Answer: The first step you should take in solving mean absolute deviation is to find the mean of the data set.

Question: In the data set 87, 94, 72, 65,97, 77, what number will you subtract from the data set to find the mean absolute deviation?
Answer: You will subtract the mean, which is 82.

Question: What is the mean absolute deviation of the data set 87, 94, 72, 65, 97, 77?
Answer: The mean absolute deviation of the data set is 10.67.

Question: Jen has a data set. When she subtracts the mean from the data set, she gets negative numbers. She added the negative numbers to the other numbers and got a negative absolute deviation. Was she correct in getting a negative mean absolute deviation? Explain.
Answer: Jen is incorrect. When calculating mean absolute deviation, you must find the mean of the absolute value of the data set.

Scatter Plots and Line of Best Fit

Question: What does a scatter plot show?
Answer: A scatter plot shows the relationship between a set of data with two variables graphed as ordered pairs on coordinate plane.

Question: What are the three types of relationships in a scatter plot?
Answer: The relationships are a positive relationship, a negative relationship, and no relationship.

Question: What is the definition of line of best fit?
Answer: A line of best fit is a line that is very close to most of the data points in a scatter plot.

Question: For an assignment, Linda gets a data set. She needs to find the mean, median and mode. Would a scatter plot be the most appropriate choice for this?
Answer: No.

Question: Joe makes a scatter plot. The points have coordinates of (2, 75), (4,110), (6, 175), (8, 210), and (10, 275). Will the line of best fit cross through all of the points? What is the relationship of the scatter plot? 
Answer: Yes; Positive; 

Box-and-Whisker Plots and Measures of Variation

Question: What do the measures of variation include?
Answer: Range, quartile, upper quartile, lower quartile, interquartile range, and outliers.

Question: What is the interquartile range of the data set 14, 18, 19, 20, 24, 29, 31?
Answer: The interquartile range is 11.

Question: What is the definition of a box-and-whisker plot?
Answer: A box-and-whisker plot is a diagram that is constructed using the median, quartiles, and extreme values. A "box" is drawn around the quartile values, and the "whiskers" extend to the extreme values.

Question: What is the first thing that you should do when drawing a box-and-whiskers plot?
Answer: The first thing that you should do is draw the box (median, and upper and lower quartiles).

Question: Draw a box-and-whiskers plot for this data set: 25, 35, 27, 22, 34, 40, 20, 19, 23, 25, 30.
Answer: The outliers should be 19 and 40. the lower quartile should be 22, the median should be 25, and the upper quartile is 34.

Circle Graphs

Question: What is the definition of a circle graph?
Answer: A circle graph is one graph that shows data as parts of a whole.

Question: When drawing a circle graph, why is it important to know the number of degrees for each section?
Answer: It is important to know the number of degrees for each section because that allows you to display your data as showing how much of a whole that section takes up.

Question: When your data values do not have a sum of 100, what do you do?
Answer: When your data values do not have a sum of 100, you need to create a ratio of the data value over the sum of all of the data values, and divide to find the decimal. When you move the decimal place 2 spaces to the right, you will get a percent that can be used in your circle graph.


Question: A circle graph of people's favorite colors are shown. the data values are: blue: 42%, red: 18%, green: 12%, and purple 28%. If 400 people were surveyed, how many more people favored purple than red? Show your work.
Answer: 40 more people favored purple than red. 28%-18%=10%. .10 of 400=40

Question: Zoe saw a circle graph of dog expenses. It had data values of 20% for vaccinations, 40% for food, 10% for toys, and 15% for other. She did not understand the circle graph because the percentage of one section, grooming supplies, was missing. What can she do to find the missing value, x? What is the percentage of the grooming supplies? Explain.
Answer: To find the missing value, Zoe needs to set up an algebraic expression: x%+sum of all known percentages=100%. So, she needs to rewrite the equation. x%+85%-100%. Then she needs to subtract 85% from both sides to get x=15%.

Stem-and-Leaf Plots and Histograms

Question: What is the definition of a histogram?
Answer: A histogram is similar to a bar graph and is used to display numerical data that have been organized into equal intervals.

Question: What is the definition of a stem-and-leaf plot?
Answer: In a stem-and-leaf plot the data are usually organized from least to greatest. The digits of the least place value usually form the leaves, and the next place-value form the stems.

Question: Amanda has to make a stem-and-leaf plot, and one of her data values is 108. How should she write this on a stem and leaf plot?
Answer: Amanda should write it as 10|8.

Question: Would a stem-and-leaf plot or a histogram be more appropriate to complete this task: Julie want to know how many kids in her class lost their first tooth at the ages of 2-3, 4-5, and 6-7.
Answer: A histogram would be more appropriate for this data.

Question: Construct a histogram of the data. Hours spent exercising per week: 3, 0, 9, 1, 4, 2, 0, 3, 6, 14, 4, 2, 5, 3, 7, 3, 0, 8, 3, 10.
Answer: See board.