Question

Pulmonary Disease

Note: You do not actually have to run analyses to answer these questions. Just interpret the coefficients reported.

The Data Set FEV.DAT on the Companion Website contains pulmonary function measures on 654 children ages 3-19 seen in East Boston, MA as part of Childhood Respiratory Disease (CRD) Study. The dataset contains data on age, sex, height (inches), FEV=volume (liters) of air expelled in 1 second, and smoking status.

We first ran a regression of FEV on smoking shown below.

##
## Call:
## lm(formula = FEV ~ Smoke, data = fev.df)
##
## Residuals:
##     Min      1Q  Median      3Q     Max
## -1.7751 -0.6339 -0.1021  0.4804  3.2269
##
## Coefficients:
##             Estimate Std. Error t value Pr(>|t|)
## (Intercept)  2.56614    0.03466  74.037  < 2e-16 ***
## Smoke1       0.71072    0.10994   6.464 1.99e-10 ***
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
##
## Residual standard error: 0.8412 on 652 degrees of freedom
## Multiple R-squared:  0.06023,    Adjusted R-squared:  0.05879
## F-statistic: 41.79 on 1 and 652 DF,  p-value: 1.993e-10

The regression coefficient for smoking is 0.7 ± 0.1, p-value < 0.001.
Does this mean that smokers have higher pulmonary function than nonsmokers? Why or why not?

Answer 1