Contents
How is a matched pair used in a study?
This study is used to investigate a cause of an illness by selecting a non-ill person as the control and matching the control to a case. The control can be matched to one or more criteria. The multicolored boxes that appear to the right of the table after data are entered represent the proportion of each value entered in the sample population.
What happens when data are matched or paired?
Recall that when data are matched or paired, we compute difference scores for each individual and analyze difference scores. The same approach is followed in nonparametric tests.
How are two samples used in statistical inference?
Two measurements (samples) are drawn from the same pair of (or two extremely similar) individuals or objects. Differences are calculated from the matched or paired samples. The differences form the sample that is used for analysis. To perform statistical inference techniques we first need to know about the
What are the characteristics of a matched sample?
When using inference techniques for matched or paired samples, the following characteristics should be present: Simple random sampling is used. Sample sizes are often small. Two measurements (samples) are drawn from the same pair of (or two extremely similar) individuals or objects.
How are matched pairs classified in a table?
Matched pairs are classified as follows: In this table, cells a and d contain counts of the concordant pairs (case-control pairs-members are same with respect to exposure status) and cells b and c contain counts of discordant pairs (case-control pairs-members are different with respect to exposure status).
How is McNemar’s test a normal approximation to the binomial?
Comments: (1) McNemar’s test is a The a normal approximation to the binomial with correction for discontinuity. If the null hypothesis were true, the test statistic would vary randomly as a chi-square random variable with 1 degree of freedom.
What should the odds ratio be for a matched pair?
In this example the odds ratio is 2.78 (89/32) and the confidence limits range from 1.86 – 4.17. (confidence limits that are above or below 1 are an indicator of significance). In this case, an odds ratio of 2.78 means that the relative risk of disease is about three times more frequent in the exposed group for the population in question.