Question

In an experiment testing a herbal extract of echinacea versus vitamin C against the common cold 60 college students in good health are randomly selected to participate. Design an experiment. Include a control group. Carry out the randomization beginning at Row 04 Column 06 in Table 1 random digits.

Answer 1

Solution: Here you have sample size of 60 students. Also you have two treatments f of herbal extract, one is echinacea and other is vitamin C. Here you can consider one group as control group and other is study/ case group. Classify/ select 30 students randomly to each of the group (Control & Study). Randomization is done using the table of random numbers by taking numbers from Row 4 and Column 6. We want 30 random numbers for our experiment.

I have provided a example for how to draw random numbers, read the steps used in the given example and apply modified steps as you want for your example.

Note: This method is one from a variety of methods of reading numbers from random number tables.

1. Assume you have the test scores for a population of 200 students. Each student has been assigned a number from 1 to 200. We want to randomly sample only 5 of the students for this demo.

2. Since the population size is a three-digit number, we will use the first three digits of the numbers listed in the table.

3. Without looking, point to a starting spot in the table. Assume we land on 75636 (3rd column, 2nd entry).

4. This location gives the first three digits to be 756. This choice is too large (> 200), so we choose the next number in that column. Keep in mind that we are looking for numbers whose first three digits are from 001 to 200 (representing students).

5. The second choice gives the first three digits to be 407, also too large. Continue down the column until you find 5 of the numbers whose first three digits are less than or equal to 200.

6. From this table, we arrive at 070 (07015), 038 (03811), 045 (04594), 055 (05542), and 194 (19428).

7. RESULT: Students 38, 45, 55, 70, and 194 will be used for our random sample.