30.11 Quick review questions

A study (Lee et al. 2016b) compared using a vegan (\(n=46\)) and a conventional (\(n=47\)) diet for 12 weeks, for a group of Koreans with Type II diabetes. A summary of the data for iron levels are shown in Table 30.4.

TABLE 30.4: Comparing the iron levels (mg) for subjects using a vegan or conventional diet for 12 weeks
Mean Std. dev n
Vegan diet 13.9 2.3 46
Conventional diet 15 2.7 47
Difference 1.1
  1. The sample size is missing from the ‘Difference’ row. What should the sample size in this row be?
  2. What is the standard deviation for the difference?
  3. What is the standard error for the difference?
  4. The two-tailed \(P\)-value for the comparison is given as \(P=0.046\). What does this mean?


Lee Y-M, Kim S-A, Lee I-K, Kim J-G, Park K-G, Jeong J-Y, et al. Effect of a brown rice based vegan diet and conventional diabetic diet on glycemic control of patients with type 2 diabetes: A 12-week randomized clinical trial. PloS One. Public Library of Science; 2016b;11(6).