Line of Best Fit Answers

A line of best fit is f(x) ≈ −0.86x + 13.5 for the set of points in the table.

Lydia runs an experiment to determine if a coin is fair by counting the number of times a coin lands heads up. The table shows her data.According to the line of best fit, about how many times would the coin land heads up in 100 flips?

Darius is studying the relationship between mathematics and art. He asks friends to each draw a "typical” rectangle. He measures the length and width in centimeters of each rectangle and plots the points on a graph, where x represents the width and y represents the length. The points representing the rectangles are (6.1, 12.0), (5.0, 8.1), (9.1, 15.2), (6.5, 10.2), (7.4, 11.3), and (10.9, 17.5). Which equation could Darius use to determine the length, in centimeters, of a "typical” rectangle for a given width in centimeters?

The scatterplot shows the time it takes for a new hot plate to boil various amounts of water, and one lab group’s attempt at a line of best fit.

Raquel throws darts at a coordinate grid centered at the origin. Her goal is to create a line of darts. Her darts actually hit the coordinate grid at (–5, 0), (1, –3), (4, 5), (–8, –6), (0, 2), and (9, 6). Which equation best approximates the line of best fit of the darts?

The graph and table shows the relationship between y, the number of words Jean has typed for her essay and x, the number of minutes she has been typing on the computer.

Rob is investigating the effects of font size on the number of words that fit on a page. He changes the font size on an essay and records the number of words on one page of the essay. The table shows his data.Which equation represents the approximate line of best fit for data, where x represents font size and y represents the number of words on one page?

Melinda works at a cafe. Each day that she works, she records x, the total dollar amount of her customers’ bills and then y, her total daily wages. The table shows her data for 2 weeks.

The graph shows the relationship between the number of ounces of cereal in a box and the price of the cereal.

Titus works at a hotel. Part of his job is to keep the complimentary pitcher of water at least half full and always with ice. When he starts his shift, the water level shows 8 gallons, or 128 cups of water. As the shift progresses, he records the level of the water every 10 minutes. After 2 hours, he uses a regression calculator to compute an equation for the decrease in water. His equation is W –0.414t + 129.549, where t is the number of minutes and W is the level of water. According to the equation, after about how many minutes would the water level be less than or equal to 64 cups?