航空公司準點誤差界限計算
場景:
航空公司隨機抽樣調查,,在信任區間 95%下,550 航班中,有 455 航班是準點。
問題:
求算母體航班準點比例。(0.8273)
求算誤差界限。(0.0316 [0.8589, 0.7957])
GNU R:
# 已知
sampleSize <- 550
numOfInterest <- 455
confidenceLevel <- 0.95
# 求算
sampleProportion <- numOfInterest / sampleSize
alpha <- confidenceLevel + (1 - confidenceLevel) / 2
z <- qnorm(alpha)
sampleProportionStdDeviation <- sqrt(((sampleProportion * (1-sampleProportion)) / sampleSize))
marginError <- z * sqrt((sampleProportion * (1 - sampleProportion)) / sampleSize)
print(sprintf("樣本數=%d 標準差=%.4f 信任區間=%.4f 誤差界限=%.4f [%6.4f, %6.4f]",
sampleSize, sampleProportionStdDeviation,
confidenceLevel, marginError, sampleProportion + marginError, sampleProportion - marginError))
# 樣本數=550 標準差=0.0161 信任區間=0.9500 誤差界限=0.0316 [0.8589, 0.7957]