Question

A study was conducted to compare three different methods of administering an intravenous (IV) injection of heparin. Each of the 150 patients in the study received a heparin injection by one of the three methods. For each patient the amount of bruising around the injection site was re corded as “bruising” and “no bruising.”

The data were recorded as follows: –

Method of Bruising - No Bruising – Injection •

A 30 20 - 50

B 10- 40- 50

C 25 25 - 50

= 65 = 85 =150

The investigator wished to determine if there were a difference in proportion of bruises for methods A, B, and C (or, identically, if there is a difference in proportion of no bruising). What statistical test is appropriate?

Answer the following Questions:

1. What type of research question is being asked?
2. What is the level of measurement of the response variable?
3. What is the research design (1, 2, 2+ groups)?
4. Were samples independently selected or were they matched?
5. What is the appropriate statistical test for analysis?

Answer 1

1. The research question being asked here is observational-relational as we have to determine the relationship if any between the bruising method & amount of bruising.

2. The level of measurement of the response variable is nominal scale (Bruising or no bruising)

3. The research design is 2+ groups (as there are three methods)

4. The samples are independently selected.

5. The appropriate statistical test for analysis is Chi Square test for independence