Q&A from AQA: The Sign Test & Significance

Below you will find a question and response from AQA in relation to: The Sign Test.

Question

What depth of teaching is required for the sign test?

Response

"Students should be able to carry out the sign test, a simple statistical test that requires minimal calculation. They would be given the necessary information to do this in an examination. There is no formula − it simply requires counting up the number of positive and negative cases in a set of data.

Example: 20 people take part in an on-line training session and at the end of it are asked to state whether they thought they now understood more, less or the same as when they started. The 15 people who say ‘more’ are given a + sign, the 3 people who say ‘less’ are given a – sign and the 2 people who say ‘the same’ are given no sign. The result of the Sign test (S) is the frequency of the least occurring sign, ignoring any cases of no difference. In this case S = 3. Students would be then be given the necessary information to enable them to comment on the probability of getting the results by chance and what this means in relation to the study, ie that the on-line training course has had a beneficial effect or not.

A full understanding of probability and significance and Type 1 and Type 2 errors is not expected at AS."

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