A researcher is investigating the linear relationship between household annual water bill ($), the number of people per household and the capacity of a backyard water tank (litres) of that household. Only households with water tanks were sampled. The researcher took a random sample and used Excel to create the following regression output.

SUMMARY OUTPUT Regression Statistics Multiple R 0.732 R Square 0.535 Adjusted R Square 0.403 Standard Error 1982.209 Observations 10 ANOVA df SS MS F Significance F Regression 2 31691171.26 15845586 4.033 0.068 Residual 7 27504078.74 3929154 Total 9 59195250 Coefficients Standard Error t Stat P-value Lower 95% Upper 95% Intercept 1420.522 1474.821 0.963 0.368 -2066.875 4907.920 People per household 344.191 140.846 2.444 0.045 11.144 677.238 Backyard water tank capacity (litres) -0.219 0.114 -1.911 0.098 -0.489 0.052