The number of cars sold annually by used car salespeople is normally distributed with a standard deviation of 17. A random sample of 470 salespeople was taken and the mean number of cars sold annually was found to be 69. Find the 95% confidence interval estimate of the population mean

Estimate mean is between 67.463 and 70.537

Step-by-step explanation: A 95% Confidence interval of a sample mean:

mean ±

α = 1 - 0.95

α = 0.05

α/2 = 0.025

z-score of α/2 = 1.96

Knowing that mean = 69, sd = 17 and there were 470 salespeople in the sample:

69 ±

69 ±

69 ±

69 ± 1.537

lower limit: 69 - 1.537 = 67.463

upper limit: 69 + 1.537 = 70.537

With a confidence of 95%, the estimate mean number of cars sold is between 67.463 and 70.537

unpaid balance is : $149.99-$50 = $99.99 new balance = 149.99+2.62-50 = $102.61 finance charge = 99.99- 0.21/12= $1.75 new balance = 99.99+1.75 = $101.74 average daily balance method average daily balance= 3399.70/30 = $113.32 finance charge = $ 0.21/12ă—113.32 = $1.98 new balance = $149.99-50+1.98 = $101.97