Ratios and effect size.

Abstract

Responding to a related pair of measurements is often expressed as a single discrimination ratio. Authors have used various discrimination ratios; yet, little information exists to guide their choice. A second use of ratios is to correct for the influence of a nuisance variable on the measurement of interest. I examine 4 discrimination ratios using simulated data sets. Three ratios, of the form a/(a + b), b/(a + b), and (a − b)/(a + b), introduced distortions to their raw data. The fourth ratio, (b − a)/b largely avoided such distortions and was the most sensitive at detecting statistical differences. Effect size statistics were also often improved with a correction ratio. Gustatory sensory preconditioning experiments involved measurement of rats’ sucrose and saline consumption; these flavors served as either a target flavor or a control flavor and were counterbalanced across rats. However, sensory preconditioning was often masked by a bias for sucrose over saline. Sucrose and saline consumption scores were multiplied by the ratio of the overall consumption to the consumption of that flavor alone, which corrected the bias. The general utility of discrimination and correction ratios for data treatment is discussed.

Excitotoxic lesions of the perirhinal cortex leave intact rats’ gustatory sensory preconditioning

“…The data of central importance are those from the test of flavours A and B. Initial examination of the data revealed a general preference for consumption of sucrose relative to saline and, therefore, scores were simply adjusted to accommodate that bias (see, Robinson, 2017 ). There was no group difference in overall consumption of either sucrose, t (15) = .327, p > .747, or of saline, t (15) = .516, p > .613.…”

Regulation of auditory fear discrimination by the novel Kv3 voltage-gated potassium channel modulator AUT00206

“…Fear discrimination during retrieval was inferred from mean freezing and darting in response to the two CS+ and two CS− presentations. Discrimination ratios calculated from mean freezing and darting in response to the CS+ and CS− during retrieval (ratio = (CS+) / (CS+ + CS−); [28]) were also determined to account for inter-individual variability in and potential drug effects on absolute freezing and darting levels. Contextual fear during retrieval was inferred from freezing and darting in the 2 min period before cue presentations and was quantified as above.…”