Makers of generic drugs must show that they do not differ significantly from nam

ID: 3150812 • Letter: M

Question

Makers of generic drugs must show that they do not differ significantly from name-brand drugs. One aspect in which drugs might differ is their extend of absorption into the bloodstream. If the generic drug is not performing as well as the name-brand ding, the absorption rate would be lower. The table below gives the data taken from a random sample of 20 healthy non-smoking male subjects who were given pairs of drugs (generic and its name-brand counterpart). The order in which individual took the ding was randomized (i.e., generic drug first or name-brand drug first). In each case, a washout period separated the two dings so that the first drug had time to disappear from the blood before the next ding was taken. For testing whether the mean absorption rate is lower for the generic ding than the namebrand ding, at-test will be used. Which one and why? What are the assumptions that need to hold for the use of this test? Use the data and a t-procedure to test whether there is evidence that the mean absorption rate is lower for the generic ding than the name-brand drug (use a=0.05). Clearly state your hypotheses, test-statistic value, p-value and your conclusion at the 0.05 level. What assumptions are required for the use of the above test procedure?

Explanation / Answer

Solutions:

Part a)

For testing whether the mean absorption rate is lower for the generic drug than the name-brand drug, a paired t-test will be used because the data is generated as the paired responses from the same persons.

Part b)

The data should be paired and the observations should be generated from two independent experiments on same subjects.

Part c)

Here, we have to test the claim by using the paired t test. The null and alternative hypothesis for this test is given as below:

Null hypothesis: H0: The mean absorption rate for the generic drug and name-brand drug is same.

Alternative hypothesis: Ha: The mean absorption rate for the generic drug is lower than the mean absorption rate for the name-brand drug.

The level of significance is given as alpha = 0.05 or 5%.

The test statistic formula is given as below:

Test statistic = t = dbar / [ Sd / sqrt(n)]

The paired t test is given as below:

Paired t Test

Data

Hypothesized Mean Difference

Level of significance

0.05

Intermediate Calculations

Sample Size

DBar

102.5000

Degrees of Freedom

945.3721

Standard Error

211.3916

t Test Statistic

0.4849

Lower-Tail Test

Lower Critical Value

-1.7291

p-Value

0.6833

Do not reject the null hypothesis

Part d)

Data should be paired and the difference should be followed an approximate normal distribution.