Scatterplots and Correlation

A baseball coach graphs some data and finds the line of best fit. The equation for the line of best fit is y = 0.32x – 20.51, where x is the number of times at bat and y is the number of hits. How many hits should he expect from a player who is at bat 175 times?

• 35 hits

• 45 hits

• 609 hits

• 62 hits

Chang wants to know if he is improving his skill on the cello. He created a scatter plot and drew a line of best fit. If he uses the point (2, 8) and (5, 1.5) from his line, which equation would best represent the line of best fit?

• y = -2.17x + 12.3

• y = 2.17x + 3.77

• y = -0.46x + 9

• y = -2.17x – 9.35

Jared collected data on the ages and heights of a random sample of elementary school students. If he plots the data on a scatter plot, what relationship will he most likely see between age and height?

• A negative correlation

• No correlation

• A positive correlation

• A constant correlation

The graph below shows the relationship between the distance in miles a delivery truck traveled and the number of hours each delivery took. Which of the two given points would be the best to use to calculate the line of best fit?

• (500, 11) and (700, 11)

• (300, 9) and (400, 7)

• (400, 9) and (500, 11)

• (300, 7) and (600, 10)

The graph shows the weights of dogs and the time it took the same dogs to complete an agility course in seconds.

Which shows the line of best fit for the data?

• 
• 
• 
• 

A principal wants to predict the number of students who will drop out of school. The equation that represents this data is y = -10x + 216, where x is the # of years & y is the # of students who drop out. Help him predict the number of students who will drop out in 2012.

• 96 students

• 21 students

• 136 students

• 156 students

Which graph represents a positive correlation?

• 
• 
• 
• 

The scatter plot shows the average yearly consumption of bottled water by people in the United States starting in 1990. Using the line of best fit, predict the average consumption of bottled water in the year 2000?

• 20 gallons

• 18 gallons

• 21 gallons

• 19 gallons

Mr. Van made a graph to represent the time his students spent studying for their test and their actual test score. Which is the correct equation for the line of best fit?

• y = 1.4x + 55

• y = 1.4x – 84

• y = 0.72x + 60

• y = 0.72 + 56

Which relationship is shown by this scatter plot?

• As the cost goes down, the number sold goes

  down.

• As the cost goes up, the number sold goes

  down.

• As the cost does down, the number sold

  remains the same.

• There is no relationship between cost and the

  number sold.