Baby birth weight raw data set7/14/2023 ![]() ![]() However, given two mothers of the same age (any age), the birth weight of an infant whose mother smokes is expected to be \( 276.3 \) grams less than the birth weight of an infant whose mother does not smoke.ī. The coefficients suggest that after controlling for a mother's smoking status, a one year increase in a mother's age will increase the predicted birth weight of her child by \( 11.2 \) grams. SAMPLE SOLUTION: fm2 = lm(birthweight ~ age smoke, data = LBW) Interpret the coefficients from this model Build a parallel slopes model for the same relationship, using the mother's smoking status as a conditioning variable. This problem continues the investigation of risk factors for low birth weight.Ī. The slope coefficient of 12.4 grams per year indicates that each additional year of a mother's age is associated with an expected increase in the birth weight of her child of 12.4 grams. SAMPLE SOLUTION: fm = lm(birthweight ~ age, data = LBW) Fit a linear regression model for this relationship, and interpret the slope coefficient. This may be a point of high leverage, given its distance from the mean age of the mothers and its departure from the general pattern of the data.ī. Finally, there is some concern about the rightmost point in the plot, which represents a large baby born to an older mother. Also, the correlation between \( birthweight \) and \( age \) is 0.09, indicating a relatively weak association between the two variables. This can be seen in the scatterplot by the relatively flat slope of the regression line. There is a relatively weak linear relationship between the birth weight and the age of mother. SAMPLE SOLUTION: xyplot(birthweight ~ age, data = LBW, xlab = "Age of mother (in yrs)", ylab = "Birth weight (in grams)", Make a scatterplot and show the least squares regression line on the plot. Investigate the relationship between birth weight and the age of the mother. Hint: try “help(LBW)” for more information about the data set (including the units of measurement)Ī. The goal of the study was to identify risk factors associated with giving birth to a low birth weight baby. A woman's behavior during pregnancy (including diet, smoking habits, and obtaining prenatal care) can greatly alter her chances of carrying the baby to term and, consequently, of delivering a baby of normal birth weight. This is due to the fact that infant mortality rates and birth defect rates are very high for babies with low birth weight. Low birth weight is an outcome that has been of concern to physicians for years. Palette = ("superpose.symbol")$col # grab the palette (theme = col.mosaic()) # get a better color scheme for lattice MTH 241 - Homework #4 - Spring 2013 MTH 241 - Homework #4 - Spring 2013 SAMPLE SOLUTION: extra credit is available if you are the first to point out an error by midnight on Thursday, February 21st require(mosaic) ![]()
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