A business wants to estimate the true mean annual income of its customers. It randomly samples 200 of its customers. The mean annual income was $52,500 with a standard deviation of $1,800. Find a 95% confidence interval for the true mean annual income of the business’ customers
A business wants to estimate the true mean annual income of its customers. The business needs to be within $100 of the true mean. The business estimates the true population standard deviation is around $2,100. If the confidence level is 95%, find the required sample size in order to meet the desired accuracy
2007-12-16 12:32:33 · 1 answers · asked by firemama 2 in Science & Mathematics ➔ Mathematics
95% interval ≈ $52,500 ± (1.96)($1,800)
$48,972 < MAI < $56,028
√n ≈ 2100*1.96/100
√n ≈ 1694.1456 ≈ 1695
2007-12-16 14:05:54 · answer #1 · answered by Helmut 7 · 0⤊ 0⤋