A seven-year medical research study reported that women...

A seven-year medical research study reported that women whose mothers took the drug DES during pregnancy were twice as likely to develop tissue abnormalities that might lead to cancer as were women whose mothers did not take the drug. a. This study compared two populations. What were the populations? b. Do you suppose the data were obtained in a survey or an experiment? c. For the population of women whose mothers took the drug DES during pregnancy, a sample of 3,980 women showed that 63 developed tissue abnormalities that might lead to cancer. Provide a descriptive statistic that could be used to estimate the number of women out of 1,000 in this population who have tissue abnormalities. d. For the population of women whose mothers did not take the drug DES during pregnancy, what is the estimate of the number of women out of 1,000 who would be expected to have tissue abnormalities? e. Medical studies often use a relatively large sample (in this case, 3,980 ). Why?

A seven-year medical research study reported that women whose mothers took the drug DES during pregnancy were twice as likely to develop tissue abnormalities that might lead to cancer as were women whose mothers did not take the drug.
a. This study compared two populations. What were the populations?
b. Do you suppose the data were obtained in a survey or an experiment?
c. For the population of women whose mothers took the drug DES during pregnancy, a sample of 3,980 women showed that 63 developed tissue abnormalities that might lead to cancer. Provide a descriptive statistic that could be used to estimate the number of women out of 1,000 in this population who have tissue abnormalities.
d. For the population of women whose mothers did not take the drug DES during pregnancy, what is the estimate of the number of women out of 1,000 who would be expected to have tissue abnormalities?
e. Medical studies often use a relatively large sample (in this case, 3,980 ). Why?

Key Concepts

Observational Study

An observational study is a type of research in which investigators observe subject behaviors and outcomes without intervening or assigning treatments. This differs from an experimental study, where researchers actively manipulate variables and apply interventions. In epidemiology, observational studies are used when it is either impractical or unethical to conduct experiments, such as studying the long-term effects of in utero exposure to a drug.

Comparison Populations

In epidemiological research, comparing distinct populations, or groups within a population, is critical for identifying differences in outcomes and potential risk factors. This involves defining exposed versus unexposed groups—in this case, one population consists of women whose mothers took DES during pregnancy and the other consists of women whose mothers did not.

Descriptive Statistics

Descriptive statistics involve summarizing and presenting the main features of a dataset using numbers such as proportions, percentages, or rates. In studies like this one, calculating the proportion of cases (e.g., tissue abnormalities per 1,000 women) within each population helps quantify the prevalence and serves as a basis for comparison between the groups.

Sample Size and Its Importance

Sample size is a critical aspect of study design in medical research because larger samples reduce the effects of random variation, increase the precision of estimates, and improve the generalizability of results. A large sample helps ensure that the findings are more representative of the target population and supports the reliability of statistical comparisons between groups.

Transcript

Please give Ace some feedback