An experiment was conducted to evaluate the effectiveness of a treatment for tapeworm in the

stomachs of sheep. A random sample of 24 worm-infected lambs of approximately the same

age and health was randomly divided into two groups. Twelve were injected with the drug and

the remaining twelve were left untreated. After a 6 month period the following worm counts

were recorded.

Treated 18 43 28 50 16 32 13 35 38 33 6 7

Untreated 40 54 26 63 21 37 39 23 48 58 28 39

(a) Explain how this design differs from the design used in Q3. That is, explain why one uses

the paired t-test and the other uses an independent two-sample t-test.

(b) Use R to perform the test of significance and find a 95% confidence interval for the true

difference in means.

(c) Write an informative conclusion.