3. Woo and McKenna investigated the effect of broadband ultraviolet B (UVB) therapy and topical calcipotriol cream used together on areas of psoriasis. One of the outcome variables is the Psoriasis...

Woo and McKenna investigated the effect of broadband ultraviolet B (UVB)
therapy and topical calcipotriol cream used together on areas of psoriasis. One of the outcome variables is the Psoriasis Area and Severity Index (PASI). The following table gives the PASI scores for 20 subjects measured at baseline and after eight treatments.
Do these data provide sufficient evidence, at the 0.01 level of significance, to
indicate that the combination therapy reduces PASI scores?

Extracted text: 3. Woo and McKenna investigated the effect of broadband ultraviolet B (UVB) therapy and topical calcipotriol cream used together on areas of psoriasis. One of the outcome variables is the Psoriasis Area and Severity Index (PASI). The following table gives the PASI scores for 20 subjects measured at baseline and after eight treatments. Do these data provide sufficient evidence, at the 0.01 level of significance, to indicate that the combination therapy reduces PASI scores? After 8 Subject Baseline Treatments 1 5.9 5.2 7.6 12.2 3 12.8 4.6 4 16.5 4.0 5 6.1 0.4 14.4 3.8 7 6.6 1.2 8 5.4 3.1 9.6 3.5 10 11.6 4.9 11 11.1 11.1 12 15.6 8.4 13 6.9 5.8 14 15.2 5.0 21.0 5.9 15 6.4 16 0.0 17 10.0 2.7 18 12.2 5.1 19 20.2 4.8 20 6.2 4.2