His contributions to measurement include innovative survey methods such as the longitudinal panel survey he used in his 1940 study in Erie, OH . He contributed to data analysis with a variety of techniques such as the 2x2 contingency tables, frequency analyses, scatter plots, and mixed methods like focus groups.
42.
Ledley s main work for the RNA Tie Club was an effort to generate a set of contingency tables for the purpose of writing a computer program that would determine the correspondence between any three-letter sequence ( triplet ) of nucleotide bases and any amino acid ( the building blocks of proteins ).
43.
To reduce the error in approximation, Frank Yates, an English statistician, suggested a correction for continuity that adjusts the formula for Pearson's chi-squared test by subtracting 0.5 from the difference between each observed value and its expected value in a 2 & times; 2 contingency table.
44.
As another example, in a contingency table with " low income ", " medium income ", and " high income " in the row variable and educational level " no high school ", " high school ", " university " in the column variable ), a rank correlation measures the relationship between income and educational level.
45.
Expert investigation of this question shows results that " strongly suggest that the extensive reporting of na�ve chi-square independence tests using cross-cultural data sets over the past several decades has led to incorrect rejection of null hypotheses at levels much higher than the expected 5 % rate . " The investigator concludes that " Incorrect theories that have been'saved'by na�ve chi-square tests with comparative data may yet be more rigorously tested another day . " Once again, the adjusted variance of a cluster sample is given as one multiplied by 1 + " d " ( " k " + 1 ) where " k " is the average size of a cluster, and a more complicated correction is given for the variance of contingency table correlations with " r " rows and " c " columns.
