Scattered Plot and Line of Best Fit

What is the line of best fit?

• A horizontal line that divides the scatter plot into two equal parts

• A vertical line that represents the average value of the data

• A curved line that connects all the data points

• A straight line that best represents the trend of the data on a scatter plot

What should the line of best fit do?

• Be parallel to the x-axis

• Only pass through the data points

• Connect all the data points directly

• Go through the 'center' of the data

What is the purpose of a line of best fit?

• To make the scatter plot look organized

• To predict outcomes not found in the data

• To calculate the exact values of all data points

• To separate the data points into two groups

How do you find the slope of the line-of-best-fit?

• By drawing a vertical line through the scatter plot

• By adding all the y-coordinates and dividing by the total number of points

• By dividing the difference in y-coordinates by the difference in x-coordinates of any two points on the line

• By finding the highest and lowest points on the scatter plot

What does the y-intercept represent in the context of a line of best fit?

• The minimum value of y in the data set

• The average value of all the y-coordinates

• The maximum value of y in the data set

• The point where the line crosses the y-axis

What is the meaning of the slope in a line-of-best-fit equation?

• The rate at which y increases as x increases

• The total number of data points in the scatter plot

• The difference between the highest and lowest values of y

• The distance between the line of best fit and the x-axis

What does the y-intercept mean in the context of pollution index and dead fish?

• The pollution index when there is 1 dead fish

• The pollution index when there are 0 dead fish

• The number of dead fish when the pollution index is 0

• The number of dead fish when the pollution index is 1

What does the slope represent in the context of pollution index and dead fish?

• The total number of dead fish each year is 112

• The total number of dead fish each year is about 9 or 10

• For every increase in the pollution index by 1 unit, there are 112 more fish deaths during the year

• For every increase in the pollution index by 1 unit, there are nine or ten more fish deaths during the year

If the pollution index is 50, how many dead fish would you predict to encounter?

• 600 dead fish

• 592 dead fish

• 580 dead fish

• 1120 dead fish

If the number of dead fish encountered is 438, what would be a good prediction of the pollution index?

• 36

• 34

• 35

• 37