5.X1 

The paper, "Serum beta-2-microglobulin (SB2M) in patients with multiple myeloma treated with alpha-interferon" [Journal of Medicine (1997) 28:311-318] reports on the influence of alpha-interferon administration in the treatment of patients with multiple myeloma (MM). Twenty newly diagnosed patients with MM were entered into the study. The researchers randomly assigned the 20 patients into the two groups. Ten patients were treated with both intermittent melphalan and alpha-interferon (treatment group), whereas the remaining 10 patients were treated only with intermittent melphalan (control group). Measurement of SB2M was performed using a radioimmune assay method 1, 3, and 6 months from the start of therapy. The measurements at one month can be accessed using the R code below.

  file <- "http://www.uvm.edu/~rsingle/stat211/data/extra/ch5_6-14.txt"
  dat<-read.table(file, header=T, na.strings=c("NA",".")) 

a) Plot the sample data for both groups using boxplots or normal probability plots. Comment on whether the assumptions for the T-test appear to be met. 

b) Using a T-test, determine if there is significant evidence of a  difference in the distribution of SB2M for the two groups.

c) Describe in plain English the implications of your findings in part (b) on the evaluation of the influence of alpha-interferon [using AT MOST TWO SENTENCES].