RANDOMIZATION AND BLINDING

1. Grace is conducting research by exposing fish to selenium. She has one control group and four treatment groups. Each group consists of five aquariums containing one fish each for a total of 25 fish used in the study. Use the random number generator online to create a randomization scheme for Grace’s study. Hint: use the third generator to obtain a random permutation of integers.

2. Create a random number assignment for 9 units (numbered one through nine) using the online random number chart. Start on row 25, column 30 and skip any repeats. To create the random number sequence, read across as if you are reading a book and record the last number of each column grouping until you have obtained all 9 numbers. (Hint: The first number is 9 and the second number is 4.)

3. Mark’s research consists of a control and two treatment groups. Each group has three individuals for a total of nine subjects. Using the online random number chart, create a random number scheme showing in which group each individual will be placed. (Hint: There are only three groups and each group should have three subjects in it when you are finished.) Start on row 14, column 50.

4. Georgia is conducting research on how simazine affects frog survivorship. She has one control and four treatment groups. Each group consists of three aquariums containing two frogs. Using the online random number chart, create a random number scheme for placing each frog into an aquarium. (Hint: Number the aquariums one through 15 and place two frogs in each aquarium.) Start with row 35, columns 29/30 and read the digits from the columns as one number (Hint: The first number is 07 or 7).

5. What is the purpose of randomization and blinding in research studies?