In: Statistics and Probability
Provide what you believe to be the research question and testable hypothesis for this study. Then, identify the independent and dependent variables in the study. (200 words minimum)
Example Study: Two hundred adults seeing an asthma nurse
specialist were randomly assigned to either a new type of
bronchodilator medication (treatment group) or placebo (control
group).
After 3 months the peak flow rates in the treatment group had
increased by a mean of 96 l/min (SD 58), and in the placebo group
by 70 l/min (SD 52). The null hypothesis is that there is no
difference between the bronchodilator medication and the
placebo.
The t statistic is 11.14, resulting in a P value of 0.001. It is
therefore very unlikely (1 in 1000 chance) that the null hypothesis
is correct so we reject the hypothesis and conclude that the new
bronchodilator is significantly better than the placebo.
The research question is:
Whether the flow rates in adult asthma patients is greater for patients who use new type of bronchodilator medication than adult asthma patients who use placebo treatment.
The testable hypotheses are as written below:
Null hypothesis: Mean of flow rates in the treatment group is same as the mean of flow rates in the placebo group
Alternative hypothesis: Mean of flow rates in the treatment group is greater than the mean of flow rates in the placebo group
The independent variable is the type of medication given to adult patients with two levels as bronchodilator medication and placebo medication.
The dependent variable in the study is the peak flow rates.
The increase in peak flow rates by bronchodilator medication after months was 96 with a standard deviation of 58 and in the placebo group, it was 70 with a standard deviation of 52.
Since the treatment group and placebo group are different hence an independent samples t-test is applied to test the difference and the test statistic obtained from the test is 11.14. The p-value for the test is 0.001 which is less the level of significance if considered 0.05.
As the p-value is less than the level of significance, we will reject the null hypothesis and conclude that the mean peak flow rates obtained by the new bronchodilator is significantly greater than the peak flow rates obtained by the placebo group.
Good luck with your studies!!!