Question

Find the population mean for the amount of money working households earn between ages 32-61.

The amounts saved are as follows: $90,500; $90,700; $92,100; $95,000; $95,300; $96,100; $98,000; $99,400; $100,000; and $100,100.

Calculate a confidence interval of 90% for the population mean.

Answer 1

From the given data, the following statistics are calculated:

n = 10

=957200/10 = 95720

s = 3691.3713

SE = s/

= 3691.3713/ = 1167.3141

= 0.10

ndf = n - 1 =9

From Table, critical values of t = 1.8331

Confidence Interval:

95720 (1.8331 X 1167.3141)

= 95720 2139.8035

= (93580.20 , 97859.80)

So,

Confidence Interval:

93580.20 < < 97859.80