Data sets and distributions

Practice sheet

Fresh questions from the whole chapter, to do on paper.

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  1. Area codes such as 770 are numbers. Is the area code of a phone number a quantitative variable?
    1. No: it is categorical, a label that only looks like a number
    2. Yes: its values are numbers
    3. Yes, a discrete quantitative variable
  2. A study measures the resting heart rate of 29 runners. What are the cases (observational units)?
    1. The 29 runners
    2. The heart rates
    3. The number 29
  3. A distribution of incomes has mean 54 thousand dollars and median 43 thousand dollars. What is its most likely shape?
    1. Skewed right: a long tail of high values pulls the mean up
    2. Skewed left
    3. Symmetric
  4. 43 students name their favorite sport. Which display suits these data?
    1. A bar chart
    2. A histogram
    3. A boxplot
  5. Which four features should you describe for the distribution of a quantitative variable (here, 42 test scores)?
    1. Shape, center, spread and unusual values (outliers)
    2. The mean, the median, the mode and the sample size
    3. The type of graph, the title, the axes and the colors
  6. A circle graph shows the favorite sports of 240 students. The soccer sector is labeled 15%. How many students chose soccer?
  7. A category is 10% of a circle graph. What is the angle of its sector, in degrees?
  8. A circle graph shows how 160 students get to school: bus 50%, walk 25%, car 25%. Which statement is true?
    1. Twice as many students take the bus as walk
    2. 50 students take the bus
    3. The sectors add up to 360 students
  9. Find the mean of the data 5, 11, 24, 33, 41.
  10. Find the median of the data 9, 14, 24, 37, 44, 79.
  11. One value in a data set is changed from 20 to 712. What happens to the mean and the median?
    1. The mean increases; the median stays about the same
    2. Both increase by the same amount
    3. The median increases; the mean stays the same
  12. Find the mean absolute deviation (MAD) of the data 8, 13, 15, 20.