computeSampleSize_Cochran
computeSampleSize_Cochran(z, p, e) ⇒ number
Estimate ideal sample size given desired confidence level, error and population proportion with attribute in question.
Implementation of Cochran's Sample Size formula
Z values for confidence levels: 50% | 0.67449 75% | 1.15035 90% | 1.64485 95% | 1.95996 97% | 2.17009 99% | 2.57583 99.9% | 3.29053
Kind: global function
Returns: number - Sample size
| Param | Type | Description |
|---|---|---|
| z | number | Standard distribution value. # of standard deviations. See statistical tables |
| p | number | Fraction of the population with attribute in question. For example if we want to estimate what time people have breakfast and we know that only 30% of people have have breakfast overall, p would be 0.3 |
| e | number | Error tolerance, 0.05 represents 5% error tolerance |