Meg plotted the graph below to show the relationship between the temperature of her city and the number of people at a swimming pool:
Main title on the graph is Swimming Pool Population. Graph shows 0 to 30 on x axis at increments of 5 and 0 to 12 on y axis at increments of 1. The label on the x axis is Temperature in degree C, and the label on the y axis is Number of People at the Pool. Dots are made at the ordered pairs 2.5, 1 and 5, 2 and 7.5, 2 and 7.5, 3 and 7.5, 4 and 10, 5 and 10, 6 and 12.5, 6 and 15, 7 and 15, 8 and 17.5, 5 and 17.5, 7 and 20, 9 and 22.5, 7 and 22.5, 9 and 25, 11 and 27.5, 12.
Part A: In your own words, describe the relationship between the temperature of the city and the number of people at the swimming pool. (5 points)
Part B: Describe how you can make the line of best fit. Write the approximate slope and y-intercept of the line of best fit. Show your work, including the points that you use to calculate slope and y-intercept. (5 points)
1 answer
Part B: To make the line of best fit, we can look for an approximate trend in the data points. By eyeballing the points, we can see that they generally follow a linear pattern.
To calculate the slope, we can choose two points that are easy to work with. Let's use the points (5, 10) and (12, 27.5):
Slope = (27.5 - 10) / (12 - 5) = 17.5 / 7 = 2.5
To calculate the y-intercept, we can pick a point and use the slope we just calculated. Let's use the point (5, 10):
y = mx + c
10 = 2.5(5) + c
10 = 12.5 + c
c = -2.5
Therefore, the equation for the line of best fit is:
y = 2.5x - 2.5