Question

Gerbils can develop gastrointestinal tract issues as they get older that may cause severe diarrhea and dehydration. A researcher wishes to conduct a study to find which of two antibiotics, Antibiotic A or Antibiotic B, is more effective in improving gastrointestinal tract health. A total of 300 Gerbils that are at least 1 years old will be randomly selected from zoos in the state of Florida. The researcher will get consent from all owners, treat the gerbils for ten months and evaluate changes in gastrointestinal health.

Part A: How would the study benefit from adding a control group?
Part B: What is the best way to randomly place the gerbils into the Antibiotic A, Antibiotic B, and control groups?
Part C: The researcher wants to use a blocking variable to place gerbils into groups instead of doing it randomly. He decides to block either by breed or zoo. Explain which would be the best blocking method.​

Answer 1

Answer is explained below.

Explanation:

a)

Adding control group will definitely benefit the study, as it will behave as the reference, or a benchmark for comparison. In order to compare and study the effects of the treatment control group is the one to compare with. So, in this way study would benefit by adding the control group, as it will become easier to know how much effective is the treatment as compared to the control group.

b)

Now, we have to randomly place the gerbils into the 1. Antibiotic A 2. Antibiotic B, and 3. control Groups

So, we have 3 groups to place gerbils randomly.

Now, we have to find the no. of replicates needed for 3 groups and 300 Gerbils.

n = t x r

n = 300

t = 3

r = ?

r = n/t

r = 300/3

r = 100 replicates will be needed.

First of all, we need to find the total number of experimental plots = n = 300

Secondly, we need to give each experimental plot a plot number in consecutive manner for example: we have 300 experimental plots

We can give numbers as 1,2,3,4,5 ...... 300

Thirdly, we need to give treatments a experimental plot picked from the random number table. For that, 300 divided by 3 = 100 numbers are to be achieved and put them in ascending or descending order.

c)

The best blocking method would be the blocking by breed of Gerbils. As in zoo, we know that, gerbils can develop gastrointestinal tract issues as they get older that may cause severe diarrhea and dehydration. But on the contrary, it gets better when it get old in case of breed of gerbils. Hence, the best blocking method would be the blocking by breed of gerbils instead by zoo.