Table 1 Analysis of before and after questions for pupils on a Likert scale (1 “strongly disagree” to 5 “strongly agree”). For each pair of responses for each question, for each pupil, the change from before to after was noted, if any, and was reduced to a binary variable, indicating increase or decrease on the Likert scale. The proportion of changes that were increases and the proportion that were decreases constitute our maximum likelihood (ML) estimates for the probability of increase and probability of decrease, conditional on a change occurring. Whether the majority of changes are in the direction of improvement is indicated, with the direction indicating improvement being a subjective judgement by the authors in the context of this study. Assuming a binomial distribution, for each question separately, the likelihood of the observed changes was calculated, firstly, assuming the ML estimates for probability of increase and decrease obtained from the data; and secondly, assuming an extrinsic hypothesis that the probability of increase and probability of decrease are equal (0.5). From these likelihoods, the likelihood ratio and its natural logarithm (Δℓ) were calculated. Rows in italics show strong evidence of overall change in a specific direction over the course of the activity (Δℓ ≥ 2). N = 12 pupils submitted both “before” and “after” questionnaires
Question | Increases | Decreases | Increases proportion | Decreases proportion | Most changes were improvements? | Likelihood ratio | Δℓ |
|---|---|---|---|---|---|---|---|
1. I will end up working in science. | 1 | 1 | 0.5 | 0.5 | No | 1 | 0 |
2. I think computers are useful within biology. | 5 | 0 | 1 | 0 | Yes | 32 | 3.47 |
3. I have heard of Linux. | 10 | 0 | 1 | 0 | Yes | 1024 | 6.93 |
4. I do not expect to enjoy [after: did not enjoy] the activity today | 4 | 3 | 0.57 | 0.43 | No | 1.07 | 0.07 |
5. I know more about computers than most adults do. | 4 | 2 | 0.67 | 0.33 | Yes | 1.40 | 0.34 |
6. I know more about computers than my teachers do. | 2 | 0 | 1 | 0 | Yes | 4 | 1.39 |
7. I am not intending to go to university. | 0 | 0 | n/a | n/a | n/a | 1 | 0 |
8. I have not heard of the Raspberry Pi. | 1 | 10 | 0.09 | 0.91 | Yes | 71.78 | 4.27 |
9. I think computers are useful within sciences other than biology. | 2 | 0 | 1 | 0 | Yes | 4 | 1.39 |
10. I would rather not use a computer, I would prefer to use a phone or a tablet. | 0 | 3 | 0 | 1 | Yes | 8 | 2.08 |
11. I cannot program a computer. | 1 | 8 | 0.11 | 0.89 | Yes | 22.17 | 3.10 |
12. I am not interested in biology. | 1 | 0 | 1 | 0 | No | 2 | 0.69 |
13. I do not enjoy using computers for fun. | 1 | 2 | 0.33 | 0.67 | Yes | 1.19 | 0.17 |
14. I am good at using a computer to analyse DNA sequences. | 8 | 1 | 0.89 | 0.11 | Yes | 22.17 | 3.10 |