Question

A multiple linear regression was performed using birth weight and gestational age to predict thyroid volume. Gestational age was included in the model because it is highly related to both thyroid volume and birth weight. The overall model was significant (p=.0001). Interpret the following regression results. Be sure to talk about all three parameters.

Parameter Estimates

Source	DF	Parameter Estimates	Standard Error	t-value	p-value
Intercept	1	336.31	168.35	2.00	0.0506
Birth Weight	1	0.1555	0.046	3.41	0.0012
Gestational Age	1	-11.5076	7.39	-1.56	0.125

Answer 1

For this regression model, the dependent or response variable is given as thyroid volume. The independent or explanatory variable or predictors for this regression model are given as birth weight and gestational age. The required regression equation for the prediction of the dependent variable thyroid volume is given as below:

Thyroid volume = 336.31 + 0.1555*Birth weight – 11.5076*Gestational age

The y-intercept for the regression equation is given as 336.31 and it is not statistically significant because the corresponding p-value is given as 0.0506 which is greater than level of significance or alpha value 0.05.

The regression coefficient of the explanatory variable birth weight is given as 0.1555 and this regression coefficient is statistically significant because the corresponding p-value is given as 0.0012 which is less than the level of significance or alpha value 0.05.

The regression coefficient of the explanatory variable gestational age is given as -11.5076 and this regression coefficient is not statistically significant because the corresponding p-value is given as 0.125 which is greater than the level of significance or alpha value 0.05.