Evidence-Based Practice for Nurses

0.15% 0.15%

2.35%

13.5%

34% 34%

13.5%

2.35%

–3 SD

<1

–2 SD

<25th

–1 SD

16 th

+1 SD

84 th

+2 SD

95 th

+3 SD

50 th 97 th

FIGURE 13-9 Percentile Rank Based on Normal Distribution

–3 SD

18.5

–2 SD

20

–1 SD

21.5

+1 SD

24.5

+2 SD

26

+3 SD

27.5

x–

23

FIGURE 13-10 Standard Deviations of Age Data

350 CHAPTER 13 What Do the Quantitative Data Mean?