We are interested in studying whether a mother's smoking affects the birthweight of her baby.

The dataset for this question is birthweight2019.csv available on Moodle. The variables you

need are as follows:

? bweight: infant birthweight (grams)

? smoke2: 1 if mother smokes 1-5 cigarettes per day, 0 otherwise

? smoke3: 1 if mother smokes 6-10 cigarettes per day, 0 otherwise

? smoke4: 1 if mother smokes 11 or more cigarettes per day, 0 otherwise

? mmarried: 1 if mother married, 0 otherwise

? mage: mother's age

Now consider a similar model but with log of birthweight as dependent variable.

Estimate this model, and report the estimated coefficients and the associated standard

errors.

ln(bweight)i = ?1 + ?2smoke2i + ?3smoke3i + ?4smoke4i + ?5magei + ?6mmariedi + ei

(b). Calculate and interpret the percentage differences in birthweight by comparing groups

smoke2, smoke3 and smoke4 with the reference group.

4. Based on the model (2), test at the 5% significance level the null hypothesis that smoking 11

or more cigarettes per day reduces birthweight by no more than smoking 6-10 cigarettes per

day, against the hypothesis that smoking 11 or more cigarettes per day reduces birthweight

by more than smoking 6-10 cigarettes per day. Write down all the steps used to conduct

your test. Keep 4 decimals for the calculation involved. (4 points)

Method: Least Squares Date: 05/12/21 Time: 23:23 Sample: 1 1200 Included observations: 1200 Variable Coefficient Std. Error t-Statistic Prob. C 8.031185 0.032162 249.7111 0.0000 SMOKE2 -0.042403 0.030313 -1.398841 0.1621 SMOKE3 -0.065921 0.025581 -2.576909 0.0101 SMOKE4 -0.101766 0.024570 -4.141835 0.0000 MAGE 0.001614 0.001283 1.258010 0.2086 MMARRIED 0.058887 0.016259 3.621730 0.0003 R-squared 0.048302 Mean dependent var 8.101898 Adjusted R-squared 0.044317 5.D. dependent var 0.224984 S.E. of regression 0.219942 Akaike info criterion -0.185917 Sum squared resid 57.75919 Schwarz criterion -0.160467 Log likelihood 117.5504 Hannan-Quinn criter. -0.176330 F-statistic 12.11994 Durbin-Watson stat 1.888703 Prob(F-statistic) 0.000000