Question

Read the brief description related to a statistical study below, and

a) explain why it is an experiment rather than an observational study

Runners recovering from lower leg fractures were randomly allocated to three different training programs. Half of each group also followed a high calcium diet. Bone density measurements were taken for all subjects.

Also:

2. b) identify the factor(s) in the experiment and the number of levels for each.

3. c) give the total number of treatments.

4. d) state the response variable(s) measured.

5. e) explain whether it was blind, or double-blind

Answer 1

a)

This is an experiment because a treatment in the form of training programs and calcium diet was deliberately imposed on the indviduals in order to observe a possible change in the response or variable (bine density) being measured.

b)

The factors in the experiments used are -

1. Training programs - Number of levels =  3

2. Calcium Diet - Number of levels = 2 (High calcium diet, No calcium diet)

c)

The total number of treatments are 3 * 2 = 6

d)

The response variable is bone density.

e)

We do not have any information that the subjects are unaware of the treatments they get. Moreover, it is not mentioned that the researchers do not know which of the groups which treatments. So, we cannot say that the study was blind, or double-blind.