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The graph at the left is a scatter plot with 35 points, each representing the population of a city and the number of auto thefts in that city, per person, per year. All 35 measurements were made in the year 2010, counting the number of auto thefts during the year and the number of residents in each city as of January 1, 2010. The dashed line runs through points (0,0) and (35,1200).

Use the drop-down menus to fill in the blanks in each of the following statements based on the information given by the graph.

The number of cities that had at least 20 auto thefts per 1,000 is closest to of the total cities measured

Every city with a population of no more than 600,000 had no more than auto thefts per 1,000 people.

There is a relationship between a city's population and its number of auto thefts per 1,000 people.





The number of cities that had at least 20 auto thefts per 1,000 is closest to 33% of the total cities measured.
  • The given information notes that there are 35 cities plotted. Counting the data points to the right of the 20-thefts-per-1000-people line, you'll find that there are 12 such cities. To quickly estimate the percentage, note that 12/36 would be exactly 1/3, or 33%, and 33% is the only answer choice that falls anywhere near the anticipated just-above-1/3 figure, so it must be correct in this "is closest to which figure" question.
Every city with a population of no more than 600,000 had no more than 30 auto thefts per 1,000 people.
  • Looking below the 600,000 population line on the graph, you'll find that the highest thefts-per-thousand data point is between the 25 and 30 gridlines, meaning that every city in that under 600,000 group fell below the 30 thefts-per-thousand mark.
There is a positive relationship between a city's population and its number of auto thefts per 1,000 people.
  • Viewing the regression line, you can note that it slopes upward and to the right - a positive slope. That slope indicates a positive relationship between population and average thefts: as the population increases, so does the rate.