Sample size for evaluating the weight and diameter of pecan fruits

The objective of this research was to determine the sample size necessary to estimate the average mass of fruit, peel and almond and longitudinal and transverse diameters of fruits of pecan (Carya illinoinensis). On 20 fruits of each of the six cultivars of pecan ('Barton', 'Imperial', 'Importada', 'Mahan', 'Moneymaker' e 'Melhorada'), the fruit mass (MF), the shell mass (MC) and almond mass (MA) was determined and measured the longitudinal diameter (DL) and transverse diameter (DT). With the data from these 20 fruits for each character and cultivar, measures of central tendency and variability were calculated, normality was checked and sample size was calculated. For each character, the homogeneity of variances among cultivars was verified and averages of cultivars were compared. Fifty fruits were enough to predict the average of MF, MC, MA, DL and DT fruit of pecan, with an estimation error equal to 5% of estimated average, with a degree confidence of 95%.