Question

The table shown to the right gives the national average​ pupil-teacher ratio in public schools over selected years. a. Find the equation for the least squares line. Let x correspond to the number of years since 1992 and let y correspond to the average number of pupils per 1 teacher. b. Use the answer from part a to predict the​ pupil-teacher ratio in 2020. Does this seem​ realistic? c. Calculate and interpret the correlation coefficient. Year Ratio 1992 17.4 1996 17.7 2000 16.9 2004 16.2 2008 15.8

Answer 1

finding equation of regression line

equation of regresion line is

y = -0.118x + 251.8

b) pupil teacher ration in 2020

y =  -0.118(28) + 251.8

y = 248.496

this is not realistic

c) correlation coefficinet r = -0.9326

which is very weak

hence ,this model is not realistic