Posted by: thefunkymonk | February 2, 2009

The Effect of Smoking and The Birth Weight of Newborns

Introduction: The purpose of this lab is to determine if there is any effect on the birth weight of newborn babies if the mother smokes cigarettes. According to “Stat Labs: Mathematical Statistics Through Application,” a low-birth weight is considered any weight below 87.5 ounces. The data was analyzed numerically and graphically in order to determine a conclusion.

Total Births:Population 1237

Total Births:Population 1237

This Table Compares the total populations numerically of smokers and non-smokers.
The Historgram of all Smokers: Population 485

The Historgram of all Smokers: Population 485

The Historgram of all Non-Smokers: Population 742

The Historgram of all Non-Smokers: Population 742

This Table Compares the total populations numerically of smokers and non-smokers.

 Results 1 : Based on these results babies of smoking mothers had a lower absolute maximum birthweight, but the lowest minimum birthweight actually belonged to a non-smoker’s baby. They also had a lower average(mean) birth weight.  This data shows that non-smoking mother’s babies have a higher mean birthweight, by roughly 4 ounces, which is not a substantial difference.  Based on the data in Table 1, of the 1236 newborn babies 485 were born to mothers that smoked and 742 were born to mothers who didn’t (10 cases were unknown). If we consider using the statistic definition of “low birth weight”, which is roughly under 90 ounces. We can see from this data that 22/742 of the non-smoking mothers, 2.96%, were of low birth weight and 36/485 of smoking mothers or 7.42% were or “low birth weight”.  All figures show negative skew, which means the mass of the distribution is concentrated to the right (higher values), but none of these numbers are substantial.

 

Using random sampling of non-smoking mothers to match the 485 smoking mothers. I got the following statistical information:

Here is a historgram comparing the Smokers to Non-Smokers using a random sampling of non-smokers to get an even population of 485.

Here is a historgram comparing the Smokers to Non-Smokers using a random sampling of non-smokers to get an even population of 485

 

A second random sampling of the Non-smokers incomparison to smokers.

A second random sampling of the Non-smokers incomparison to smokers.

 Results:

 

  Min Max Mean St. Dev. Skew
Rand S1 55 174 123.26349 16.98804 -0.23700
Rand S2 62 176 123.96058 16.50857 -0.10841
Smokers 58 163 114.10950 18.09895 -0.03370

 

 

This data shows that even with taking a random sampling to compare the 485 smokers in this survey to 485 randomly selected non-smokers, the average birthweight of babies is lower when their mother smokes.  Also using the statistical definition of low birthweight to be less then 90 ounces we found smoking mothers to be averaging  7.42% low birthweight births and nonsmokers to have 2.96%. These randomly selected non-smoking statistics showed 16/485 and 12/485, or 3.29% and 2.47%, which is much less then the smoking mothers.

 Equations:

Mean:AM=\frac{1}{n}\sum_{i=1}^na_i

Standard Deviation:    untitled2

Skewness:    untitled1

File:Skewness Statistics.svg

Conclusion:

It is difficult to analyze the question if smoking during pregnancy effects the birth weight of the child. The facts are that there are more than 45% more non-smokers than smokers in the given data and given this non-smokers had skewness closest to normal distribution. The data shows that the mean weight for smokers is nearly 9 ounces less than average weight of non-smokers. This is probably the most significant statistic in this data. Also using the randomly sorted data, each outcome showed that smokers had more low birthweight births. Theis evidence shows that it is strongly likely that smoking during pregnancy can cause low birthweights in your children. Don’t Do it!

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