Question

Use the margin of error of 4, confidence interval of 90% and ?=28 to find the minimum sample size required to estimate an unknown population mean ?.

Answer 1

The following information is provided,
Significance Level, α = 0.1, Margin or Error, E = 4, σ = 28

The critical value for significance level, α = 0.1 is 1.64.

The following formula is used to compute the minimum sample size required to estimate the population mean μ within the required margin of error:
n >= (zc *σ/E)^2
n = (1.64 * 28/4)^2
n = 131.79

Therefore, the sample size needed to satisfy the condition n >= 131.79 and it must be an integer number, we conclude that the minimum required sample size is n = 132
Ans : Sample size, n = 132

### if you take z value upto 3 deciamal answer would be change