Q) To Study the effect of an antiviral drug, we note down the initial viral load and then after a month repeat viral load. What is the the most appropriate statistical test of significance to test the change in viral load
(a) Paired t-test (b) Unpaired or independent t-test (c) Analysis of variance (d) Chi-square test
Ans a) Paired t test
paired t test is used When comparing the same person results after giving a drug or doing a surgery or any intervention
A paired t-test is used when we are interested in the difference between two variables for the same subject. Often the two variables are separated by time
Unpaired t test
The unpaired two-samples t-test is used to compare the mean of two independent groups.
For example, suppose that we have measured the weight of 100 individuals: 50 women (group A) and 50 men (group B). We want to know if the mean weight of women is significantly different from that of men In this case, we have two unrelated (i.e., independent or unpaired) groups of samples. Therefore, it’s possible to use an independent t-test to evaluate whether the means are different.
The basic idea behind the test is to compare the observed values in your data to the expected values that you would see if the null hypothesis is true.
To determine whether the association between two qualitative variables is statistically significant
Analysis of Variance ANOVA example
A group of psychiatric patients are trying three different therapies: counseling, medication and biofeedback. You want to see if one therapy is better than the others.
Postoperative pulmonary complications occur in approximately 6% of patients after major abdominal operations and
It includes pneumonia/infection, respiratory failure requiring prolonged ventilation, exacerbation of chronic obstructive pulmonary disease (COPD), and lobar/parenchymal collapse with or without associated effusion.
More recently, standard patient care protocols (e.g., iCough) have been developed to decrease the risk of pulmonary complications, which include incentive spirometry, coughing and deep breathing, oral care
(brushing teeth and using mouthwash), elevating the head of bed,
and getting out of bed three times a day.