What test can be performed to compare the variances of the two groups?

Orthopedics

A study was performed among patients with piriformissyndrome (PS), a pelvic condition that involves malfunction of the piriformis muscle (a deep buttock muscle),which often causes lumbar and buttock pain with sciatica (pain radiating down the leg). A randomized double-blind clinical trial was performed where patients were injected with one of three substances:

Group 1: TL group received an injection of a combination of triamcinolone and lidocaine.

Group 2: Placebo group received a placebo injection.

Group 3: Botox group received a Botox injection.

We will focus on a comparison of group 3 vs. group 2 for this problem. Patients were asked to come back at 2 weeks, 1 month, 2 months, etc., up to 17 months. At each visit the patients rated their percentage of improvement of pain vs. baseline on a visual analog scale with a maximum of 100% of improvement (indicated by 100). The results at the 3-month follow-up visit were as follows:

Table 8.41: Percent improvement in the Botox Study at 3 months of follow-up

 

Assume normality of the distribution of percent improved.

Transcribed Image Text:

Group Mean sd Placebo (2) Botox (3) 19.8 49.7 20.9 11 38.2 19