Archmage only.

  Hip pain is not always associated with hip degeneration that requires hip replacement surgery.  Many times the patient has an impingement syndrome and an injection of a steroid into the joint space relieves the pain.  For those patients for which the injection is not sufficient, they may undergo an arthroscopic surgery to remove the defect in the hip space.  This study will look at the rates of pain vs. no pain for those receiving injections and the rate of pain vs. no pain for those patients that must have reparative surgery.

 

	Pain	No Pain
Hip surgery	10	40
Hip injection	13	27

 

Null hypothesis:   The rate of not having hip pain is independent of whether the patient had hip surgery or a hip injection.

 

Ho:  the row and column variables are independent.

 

Research hypothesis:  The rate of not having hip pain is dependent on the treatment.

 

H1:  the row and column variables are dependent.

 

The sample population is taken from a grouping of patients who have hip pain.

The sample size is 100 patients.

The population of interest is those patients who have no pain post treatment.

This small sample size may or may not represent all patients who have hip pain.

 

The independent variable is level of pain.

The dependent variable is the treatment.

 

I will apply the Test Statistic for a Test of Independence (Triola, 2010):

 

 X2 = sum of (observed – expected)^2/e

Alpha = .05

As calculated by STATDISK the results are as follows:

Degrees of freedom:  1

Test Statistic, X^2: 1.8251

Critical X^2:        3.841456

P-Value:             0.1767

 

Fail to Reject the Null Hypothesis

Data does not provide enough evidence to conclude that the rows and columns are related

 

The P-value = 0.1767

The α = 0.05. 

 

Since the P-value is greater than the alpha and the X^2 is less than the critical value X^2, either can be used to make the conclusion to fail to reject the null hypothesis.

 

Triola, M. F. (2010). Elementary Statistics, Eleventh Edition. Pearson.