Unit Test — Unit test Answers

Which graph shows a negative correlation?

Ms. Sutton recorded the word counts and scores of the top ten essays in a timed writing contest. The table shows her data.How does the word count of an essay relate to its score in the contest?

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.

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.

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?

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?

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?

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?

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?

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.

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?

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?

Which table shows a negative correlation?

Mr. Palmer does an experiment to investigate the effects of distractions on studying and learning. He gives each participant a line with 10 words to memorize in 5 minutes. Some of the participants are interrupted during the 5 minutes with text messages from friends. The graph shows the number of words remembered after 5 minutes and the number of text messages sent to the participants as distractions.

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

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

Latitude and longitude describe locations on the Earth with respect to the equator and prime meridian. The table shows the latitude and daily high temperatures on the first day of spring for different locations with the same longitude.Which statement describes the slope of the line of best fit for the data?

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.