Question

Simple regression was employed to establish the effects of childhood exposure to lead. The effective sample size was about 122 subjects. The independent variable was the level of dentin lead (parts per million). Below are regressions using various dependent variables.

(a) Calculate the t statistic for each slope. From the p-values, which slopes differ from zero at α = .01? (Round your answers to 2 decimal places. Negative values should be indicated by a minus sign.)

Dependent Variable	R2			Estimated Slope			Std Error			tcalculated			p-value				Differ from 0?
Highest grade achieved		0.050			-0.029			0.010						.004			(Click to select)  No  Yes
Reading grade equivalent		0.126			-0.093			0.022						.000			(Click to select)  Yes  No
Class standing		0.078			-0.005			0.002						.014			(Click to select)  Yes  No
Absence from school		0.073			4.700			1.620						.004			(Click to select)  No  Yes
Grammatical reasoning		0.090			0.132			0.070						.062			(Click to select)  Yes  No
Vocabulary		0.119			-0.196			0.002						.000			(Click to select)  Yes  No
Hand-eye coordination		0.035			0.060			0.027						.028			(Click to select)  No  Yes
Reaction time		0.016			9.300			3.560						.010			(Click to select)  No  Yes
Minor antisocial behavior		0.037			-0.819			0.579						.160			(Click to select)  Yes  No

(b) It would be inappropriate to assume cause and effect without a better understanding of how the study was conducted.

• No

• Yes

Answer 1