Question

A large study of caffeine intake during pregnancy was conducted to evaluate the effects of reducing caffeine intake on birth weight and length of gestation. The following statistics were collected for women who eliminated caffeinated drinks from their diet during the last trimester of their pregnancy.

Number of babies studied: 96
Mean weight of parturition: 3520 g
Standard deviation of weights of parturition: 210 g
If babies from the population of women consuming four or more caffeinated drinks/day have a mean weight of 3450 g and a standard deviation of 240 g, can you demonstrate with the study data that eliminating caffeine consumption raises birth weights and makes them less variable?

Answer 1

Comparing the provided statistics on birth weights, women who eliminated caffeine had a higher mean weight and lower standard deviation than those consuming four or more caffeinated drinks per day. A t-test could determine significance for mean differences, while an F-test could evaluate the significance of variability differences, but actual test calculations cannot be performed with the information given.

Step-by-step explanation:

To evaluate whether eliminating caffeine consumption raises birth weights and makes them less variable, we can compare the means and standard deviations of the two groups: women who eliminated caffeine and those who consumed four or more caffeinated drinks per day during their last trimester of pregnancy.

The statistics for the women who eliminated caffeine are as follows:

• Number of babies studied: 96
• Mean weight of parturition: 3520 g
• Standard deviation of weights: 210 g

The statistics for the women consuming four or more caffeinated drinks per day are:

• Mean weight of parturition: 3450 g
• Standard deviation of weights: 240 g

To determine if the mean weight of parturition is significantly different between the two groups, a statistical test such as an independent samples t-test could be used. However, we cannot perform this test with the data provided because we do not have individual data points or the standard error of the mean. Conceptually, if the t-test were conducted and resulted in a p-value less than 0.05, we could conclude that there is a statistically significant difference between the two groups in terms of birth weight.

Regarding the variability, we can compare the standard deviations of both groups directly. The group that eliminated caffeine consumption has a standard deviation of 210 g, which is smaller than the 240 g standard deviation of the group consuming four or more caffeinated drinks per day. A smaller standard deviation indicates less variability, suggesting that birth weights might be less variable in the caffeine-free group. However, to draw a definite conclusion, a statistical test such as F-test for comparison of variances could be applied to assess if this difference in variability is statistically significant.