Line of Best Fit Answers

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?

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

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 table shows the ages and weights of babies at a hospital.What is the correlation between age and weight as shown 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?

Teddy is preparing to sell some wooden blocks at a garage sale. Before pricing individual bags of blocks, he decides to determine the approximate number of blocks per pound by researching the weights of different sets of blocks. The graph shows his data.

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?

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 table shows the temperature of an amount of water set on a stove to boil, recorded every half minute.According to the line of best fit, at what time will the temperature reach 100°C, the boiling point of water?

Payton collected data to show the relationship between the number of hours he practices and the number of errors he makes when playing a new piece of music. The table shows his data.Which is the approximate slope of the line of best fit for the data?