Back to Fit a linear function to a scatter plot — Problem 5 · Task Set 8

Exercises: Fitting a Linear Function to a Scatter Plot

Work through each section in order. When a scatter plot is shown, first decide whether it suggests a LINEAR association before fitting a line. To find a line's equation, read two convenient points ON the line (not necessarily data points), compute slope as rise over run, and find the y-intercept. Remember: a line of fit balances points above and below and need not pass through any data point.

Grade 9·22 problems·~35 min·Common Core Math - HS Statistics and Probability·standard·hss-id-b-6c

Work through problems with immediate feedback

Fluency Practice

Read scatter plots, judge form, and find or use line equations.

A student eyeballs a line of fit as $y = 5x + 53$ . Their calculator's least-squares regression line is $y = 5.8x + 51$ . Is the student's hand-drawn line wrong?

No. A reasonable eyeballed line is close to the regression line but not identical; small differences are expected.

Yes. The hand-drawn line must match the regression line exactly or it is wrong.

Yes. The regression line is wrong because it disagrees with the student.

It is impossible to tell without re-plotting every point.