The agreement between visual analysis and the results of the split-middle method of trend estimation was examined using a set of 24 stimulus graphs and 30 raters. Results revealed poor agreement between the two methods, and low sensitivity, specificity, and predictive ability for visual analysis in relation to statistical inferences. (JDD)

The focus of this study was on the relationship between visual and statistical analyses of time series data and the degree to which characteristics of the data influenced this relationship. A total of 52 teachers took part in evaluating a series of graphs having prespecified characteristics. The independent variables manipulated included: slope,…