Does your IQ depend on the size of your brain? A group of female college students took a test that measured their verbal IQs and also underwent an MRI scan to measure the size of their brains (in 1000s of pixels). The scatter plot and regression analysis are shown, and the assumptions for inference were satisfied.

Dependent variable is IQ Verbal
R-squared = 6.5%

a) Test an appropriate hypothesis about the association between brain size and IQ.
b) State your conclusion about the strength of this association.

120 100 80 t 800 850 900 950 Brain Size (1000 pixels) Variable Coefficient SE(Coeff) Intercept 24.1835 76.38 Size 0.0988 0.088