If the population standard deviation is unknown and we wish to calculate the sample size required to ensure our confidence interval has a margin of error e, What must we do? 1) Use the formula n = (Z * σ / e)² 2) Use the formula n = (Z * σ / e)² and round up to the nearest whole number 3) Use the formula n = (Z * σ / e)² and round down to the nearest whole number 4) Use the formula n = (Z * σ / e)² and round to the nearest whole number
