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

answer: c, the green line

step-by-step explanation:

there is no black line, eliminate b.

simple interest implies periodic payments, but the red line shows no payments, eliminate d.

simple interest has equal payments. if paid say every day, the graph is about a straight line (actually a stairstep).

the yellow line is not straight, eliminate a.

check: the green line is straight, answer is c.

simple interest with positive interest rate gives a straight line sloping up to the right. green line:

g(t) = $100 + ($200-$100) ÷ (20 years) × (t years)

= $100 + (4%/year) × ($100)(t years)

incidentally, the yellow line curving upward represents continuously compounded interest

y = $100 × 2^(t years / (14 assuming the yellow line hits $200 at 14 years. 2^0 is 1, so y(0) = $100; 2^(14/14) is 2, so y(14) = $200.

98%

step-by-step explanation: