Skip to main content


Table 9 Comparison of pre- and post-intervention knowledge scores between trial arms

From: Early warning scoring systems versus standard observations charts for wards in South Africa: a cluster randomized controlled trial

Intervention arm (n = 25) Control arm (n = 25) Independent t-test for mean differences in pre- and post-intervention scores between trial arms
Mean score difference (%, SD) 95% CI Mean score difference (%, SD) 95% CI Mean score difference (%, 95% CI) t-value (df) Pvalue
4/23 (19.5, 25.6) 8.9-30.0 1/23 (4.0, 13.2) −1.5-9.5 3/23 (15.5, 3.8-27.2) 2.69 (35.9) equal variances not assumed 0.011
  1. Data were normally distributed and parametric tests were used.
  2. The 95% CI values with minus signs indicate a wide standard deviation within the greater population of nurses, particularly in the control wards, indicating that the sample size may be too small.
  3. Note: test material is available to reviewers and editors on request. CI, confidence interval, SD, standard deviation; df, degrees of freedom.