Vignette: A researcher is conducting a study to determine the effectiveness of a new drug in the treatment of hypertension. The study involves 100 subjects who are divided into 2 groups: group A receives the new drug and group B receives a placebo. The researcher measures the reduction in systolic blood pressure after 12 weeks. The researcher finds that the systolic blood pressure is significantly reduced in group A compared to group B. However, the researcher is not sure if the difference in blood pressure reduction is due to the new drug or due to chance.
Which of the following is the best statistic for the researcher to use to determine if the difference in blood pressure reduction between group A and group B is due to chance?
D) Standard deviation
The P-value is a statistical measure that helps scientists determine whether their hypotheses are correct. It is used in hypothesis testing to help you support or reject the null hypothesis. It represents the probability that the results of your test occurred at random. If the P-value is less than (or equal to) a predetermined threshold (usually 0.05), you reject the null hypothesis, indicating that the observed difference is unlikely to have occurred by chance, and is statistically significant. In the context of this study, a P-value less than 0.05 would suggest that the difference in blood pressure reduction between the two groups is statistically significant, and is likely due to the effect of the new drug, not chance. Therefore, it is the correct answer. The other options (mean, median, mode, and standard deviation) are measures of central tendency and dispersion, but do not provide information on the probability that the observed results could have occurred by chance.