Tamanho de amostra para estimação do coeficiente de correlação de Pearson entre caracteres de Crambe abyssinica

Filho, Alberto Cargnelutti; Lopes, Sidinei José; Toebe, Marcos; Silveira, Tatiani Reis da; Schwantes, Ismael Albino

doi:10.1590/s1806-66902011000100019

Cited by 17 publications

(18 citation statements)

References 21 publications

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“…These values were similar to those observed in turnip (CARGNELUTTI FILHO et al, 2014). Plant height measurements during the second season fluctuated from a minimum of 2 to a maximum of 327 cm, and the variance ranged from 3.19 to 1,731.10 cm 2 .…”

Section: Resultssupporting

confidence: 85%

“…During the second season, the data were similar to the first, but with higher values ranging from 16.41% to 31.04%, where the largest variability was at the beginning of the crop cycle. The plant height CV values were similar to those of plant height at maturity, and the number of nodes per plant in a soybean culture (CARGNELUTTI FILHO et al, 2009) and were similar to those for the plant height of crambe (CARGNELUTTI FILHO et al, 2011). These results suggest that at the beginning of the cycle, in both years, a larger sample size is required to estimate mean plant height, and in the second season, a larger sample size should be permitted in comparison to the first season.…”

Section: Resultssupporting

confidence: 71%

“…In a different study in a soybean crop, with estimation error equal 5% of the mean estimate, the sample size used to estimate the mean number of nodes ranged from 32 to 115 (CARGNELUTTI FILHO et al, 2010). Plant height sample size values used to estimate the mean displayed a similar trend compared with the number of nodes, ranging from 130 to 678 plants in the first season, to 261 to 932 plants in the second season.…”

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confidence: 90%

“…The ideal sample size has been determined to estimate the mean of morphological traits in crops, such as soybean (CARGNELUTTI FILHO et al, 2009), castor bean (CARGNELUTTI FILHO et al, 2010), other bean crops (CARGNELUTTI FILHO et al, 2008) and turnip (CARGNELUTTI FILHO et al, 2014). However, similar studies for pigeonpea have not been conducted.…”

Section: Introductionmentioning

confidence: 99%

“…These results prove that greater variability is present at the beginning of the crop cycle (Table 4). The variability of the estimate of the sample size for the traits: number of nodes on the stem, plant height and stem diameter, was found in three soybean cultivars (ESTEFANEL et al, 1984). Cargnelutti Filho et al (2010 found variability in the ideal sample size for the number of nodes in 28 soybean genotypes.…”

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confidence: 99%

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Sample size for morphological traits of pigeonpea

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Filho

Lúcio

et al. 2015

SCA

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The objectives of this study were to determine the sample size (i.e., number of plants) required to accurately estimate the average of morphological traits of pigeonpea (Cajanus cajan L.) and to check for variability in sample size between evaluation periods and seasons. Two uniformity trials (i.e., experiments without treatment) were conducted for two growing seasons. In the first season (2011/2012), the seeds were sown by broadcast seeding, and in the second season (2012/2013), the seeds were sown in rows spaced 0.50 m apart. The ground area in each experiment was 1,848 m 2 , and 360 plants were marked in the central area, in a 2 m × 2 m grid. Three morphological traits (e.g., number of nodes, plant height and stem diameter) were evaluated 13 times during the first season and 22 times in the second season. Measurements for all three morphological traits were normally distributed and confirmed through the Kolmogorov-Smirnov test. Randomness was confirmed using the Run Test, and the descriptive statistics were calculated. For each trait, the sample size (n) was calculated for the semiamplitudes of the confidence interval (i.e., estimation error) equal to 2, 4, 6, ..., 20% of the estimated mean with a confidence coefficient (1-α) of 95%. Subsequently, n was fixed at 360 plants, and the estimation error of the estimated percentage of the average for each trait was calculated. Variability of the sample size for the pigeonpea culture was observed between the morphological traits evaluated, among the evaluation periods and between seasons. Therefore, to assess with an accuracy of 6% of the estimated average, at least 136 plants must be evaluated throughout the pigeonpea crop cycle to determine the sample size for the traits (e.g., number of nodes, plant height and stem diameter) in the different evaluation periods and between seasons. Key words: Cajanus cajan L., sample dimensioning, experimental precision ResumoOs objetivos deste estudo foram determinar o tamanho de amostra (número de plantas) para estimação da média de caracteres morfológicos de feijão guandu (Cajanus cajan L.) e verificar se há variabilidade do tamanho de amostra entre as épocas de avaliação e entre os anos agrícolas. ensaios de uniformidade (experimentos sem tratamentos), em dois anos agrícolas. No primeiro ano agrícola (2011/2012), a semeadura foi realizada a lanço e no segundo ano agrícola (2012/2013), a semeadura foi realizada em linhas espaçadas a 0,50 m. A área útil, em cada um dos experimentos foi de 1.848 m 2 , e foram demarcadas 360 plantas, na área central, em um gride de 2 m × 2 m. Foram avaliados três caracteres morfológicos (número de nós, altura de planta e diâmetro de caule) em 13 épocas no primeiro ano agrícola e em 22 épocas no segundo ano agrícola. Em todos os caracteres foi verificada a normalidade, por meio do teste de Kolmogorov-Smirnov e a aleatoriedade pelo Run Test e calculadas as estatísticas descritivas. Para cada caractere, foi calculado o tamanho de amostra (n), para as semiamplitudes do intervalo de confiança (...

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Section: Resultssupporting

confidence: 85%

Section: Resultssupporting

confidence: 71%

mentioning

confidence: 90%

Section: Introductionmentioning

confidence: 99%

mentioning

confidence: 99%

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Sample size for morphological traits of pigeonpea

Facco

Filho

Lúcio

et al. 2015

SCA

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Use of allometric models to estimate leaf area in Hymenaea courbaril L.

Santos

Costa

Silva

et al. 2016

Theor. Exp. Plant Physiol.

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Sample size for estimation of the Pearson correlation coefficient in cherry tomato tests

et al. 2017

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The aim of this study was to determine the required sample size for estimation of the Pearson coefficient of correlation between cherry tomato variables. Two uniformity tests were set up in a protected environment in the spring/summer of 2014. The observed variables in each plant were mean fruit length, mean fruit width, mean fruit weight, number of bunches, number of fruits per bunch, number of fruits, and total weight of fruits, with calculation of the Pearson correlation matrix between them. Sixty eight sample sizes were planned for one greenhouse and 48 for another, with the initial sample size of 10 plants, and the others were obtained by adding five plants. For each planned sample size, 3000 estimates of the Pearson correlation coefficient were obtained through bootstrap re-samplings with replacement. The sample size for each correlation coefficient was determined when the 95% confidence interval amplitude value was less than or equal to 0.4. Obtaining estimates of the Pearson correlation coefficient with high precision is difficult for parameters with a weak linear relation. Accordingly, a larger sample size is necessary to estimate them. Linear relations involving variables dealing with size and number of fruits per plant have less precision. To estimate the coefficient of correlation between productivity variables of cherry tomato, with a confidence interval of 95% equal to 0.4, it is necessary to sample 275 plants in a 250m² greenhouse, and 200 plants in a 200m² greenhouse.

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Tamanho de amostra para estimação do coeficiente de correlação de Pearson entre caracteres de Crambe abyssinica

Cited by 17 publications

References 21 publications

Sample size for morphological traits of pigeonpea

Sample size for morphological traits of pigeonpea

Use of allometric models to estimate leaf area in Hymenaea courbaril L.

Sample size for estimation of the Pearson correlation coefficient in cherry tomato tests

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