A.11 Answers to Lecture 11 tutorial

A.11.1 Answers to Sect. 11.6

\(t\)-test: Age as it is the only quantitative variable. The rest would use a chi-square test. Between the ‘alive’ and ‘dead’ groups, there is evidence that the proportion with diabetes is different and whether or not a (prosthetic) limb was fitted.

A.11.2 Answers to Sect. 11.7

1. P: school age children with ambulatory cerebral palsy; O: In this case, the hand-writing legibility; C: Between scores made when using standard and specialty furniture; I: The furniture configurations imposed. 2. True experiment, as treatments were imposed (experiment), and the researchers allocated children to the groups (true experiment). 3. Unit of observation: Each students. Unit of analysis: Each student, as the two measurements from each student are related to the same person. The students are compared. So this is a paired analysis. A paired-\(t\) test. 4. Blinding not used, as students would know the desk configurations were different. No blinding, so double blinding is not used. However: The assessors are blinded to the intervention, as assessor unaware of furniture configuration, so assessor does not influence outcomes (unintentionally). 5. Sample mean: \(30.7\); \(s=3.3\). 6. Standard errors \(\text{s.e.}(\bar{x})=3.3\div\sqrt{30} = 0.60249\); the approximate CI is \(30.7\pm(2\times0.60249)\), or \(30.7\pm 1.2\); from \(29.5\) to \(31.9\). 7. The sample provides no evidence (paired \(t\): \(-0.30\); \(\text{df}=29\); two-tailed \(P=0.77\)) of a population mean difference between the handwriting legibility when performed using standard (\(30.7\); standard deviation: \(3.3\)) and speciality furniture configurations (\(30.6\); \(3.3\); 95% CI for the difference from \(-0.8\) to \(0.6\)). 8. No.

A.11.3 Answer to Sect. 11.8

1. P: Medical ‘teams’ working in paediatric resuscitations; O: Number and type of drug errors; C: None; I: None. 2. Descriptive. 3. Prospective observational. 4. For example: Study is only a mock (not real) situation, due to ethics. Hawthorne effect: subjects know they are being watched.