Sample dimension for evaluating physical and chemical characters of wild passion fruit

ABSTRACT The objective of this study was to determine the sample size required to evaluate physical and chemical characters of Passiflora foetida fruits. A hundred and fifty fruits were randomly harvested from plants grown in a greenhouse. In the laboratory, these fruits were measured for 12 characters (length, equatorial diameter, fruit mass, bark mass, pulp mass, pulp yield, seed weight per fruit, number of seeds per fruit, seed mass per fruit, titratable acidity, soluble solids, and ratio) and the measures of central tendency and dispersion were calculated and checked for normality. The bootstrap percentile confidence interval was determined, from the simulation of 4,000, for 150 sample sizes (1, 2, ..., 150 fruits) measured for each character. The physical and chemical characteristics evaluated in mature fruits of P. foetida exhibit different experimental accuracies and require different sample sizes. To measure only the longitudinal length, equatorial diameter and the relationship among these six fruits are sufficient to estimate the average estimation error with a 5% average. If we consider all the physical and chemical characters of ripe fruit in this work, at least 39 fruits are required, assuming 10% error of the estimated average.