Sample size to estimate the mean of traits in jack bean

Abstract

In experiments, it is important to evaluate sufficient number of plants, so that inferences have the desired precision. The objective of this research was to determine the sample size (i.e., number of plants) required to estimate the mean of jack bean traits (Canavalia ensiformis) with precision levels. In experimental area of 10 × 16 m (160 m2), 194 plants were collected randomly at 202 days after sowing. The morphological (plant height, stem diameter, number of nodes, and number of leaves) and productive traits (number of pods, fresh matter of pods, fresh matter of aerial part without pods, fresh matter of aerial part, dry matter of pods, dry matter of aerial part without pods, and dry matter of aerial part) were measured in each plant. Measures of cen­tral tendency, variability, skewness, and kurtosis were calculated for each trait. The sample size was determined by resampling with replacement of 10,000 resamples. In order to estimate the mean of morphological and productive traits of jack bean with the amplitude of the confidence interval of 95% equal to 40% of the estimated mean, 114 plants are required.