Chapter 2: Q112E (page 125)

Treating psoriasis with the “Doctorfish of Kangal.”Psoriasis is a skin disorder with no known cure and noproven effective pharmacological treatment. An alternative treatment for psoriasis is ichthyotherapy, also known as therapy with the “Doctorfish of Kangal.” Fish from the hot pools of Kangal, Turkey, feed on the skin scales of bathers, reportedly reducing the symptoms of psoriasis. In one study, 67 patients diagnosed with psoriasis underwent 3 weeks of ichthyotherapy (Evidence-Based Research in Complementary and Alternative Medicine,December 2006). The Psoriasis Area Severity Index (PASI) of each patient was measured both before and after treatment. (The lower the PASI score, the better is the skin condition.) Box plots of the PASI scores, both before (baseline) and after 3 weeks of ichthyotherapy treatment, are shown in the accompanying diagram.
a.Find the approximate 25th percentile, the median, and the 75th percentile for the PASI scores before treatment.
b.Find the approximate 25th percentile, the median, and the 75th percentile for the PASI scores after treatment.
c.Comment on the effectiveness of ichthyotherapy in treating psoriasis.

Short Answer

Expert verified

(a) 10,15, 28

(b) 1, 3, 6

Step by step solution

Finding the median, lower quartile, and upper quartile

25^th percentile = 10

Median = 15

75^th percentile = 28

Approximating the median, lower quartile, and upper quartile

25^th percentile = 1

Median = 3

75^th percentile = 6

Commenting on the effectiveness of the ichthyotherapy

After looking at the results, we can conclude that ichthyotherapy can be used as a treatment to reduce the PASI scores. It is visible from the box plot that post-treatment, almost 75% of patients have a PASI score less than 10, whereas, before the treatment, these scores were at 30. The treatment is very effective in reducing the symptoms of ichthyotherapy.