Question

Questions 6-10 are related to the following As a statistics course assignment you are to build a 95% confidence interval for the mean monthly rental for two-bedroom apartments in Marion County. A random sample of 80 apartments yields the following data. 840 1550 560 1080 970 1560 830 1220 1390 1110 920 1150 1600 1310 610 1590 1100 720 720 1350 1020 1290 710 600 830 1190 1170 1470 1320 730 800 840 1130 690 900 1520 1050 1220 1400 1060 1420 560 1580 790 1240 1530 1010 510 540 1600 560 1520 1350 580 600 1600 1160 880 1320 720 1080 1400 620 1430 1560 800 1530 650 700 1400 1430 970 1230 1100 1370 1120 1290 1130 1010 1310 6 The point estimate of the mean monthly rental is, a 1038.45 b 1059.60 c 1081.25 d 1091.50 7 The variance of the sample mean is, a 1,374.275 b 1,649.130 c 34,631.738 d 109,942.025 8 The margin of error for the 95% confidence interval is, a 68.2 b 73.8 c 76.7 d 80.6 9 The upper end of the 95% interval estimate is, a 1123.9 b 1149.4 c 1165.3 d 1175.8 10 If you were asked to narrow the 95% margin of error to $25. How many apartments would you need to include in your sample? For planning value use $300. a 620 b 585 c 554 d 485.

Answer 1

Questions 6-10 are related to the following As a statistics course assignment you are to build a 95% confidence interval for the mean monthly rental for two-bedroom apartments in Marion County. A random sample of 80 apartments yields the following data. 840 1550 560 1080 970 1560 830 1220 1390 1110 920 1150 1600 1310 610 1590 1100 720 720 1350 1020 1290 710 600 830 1190 1170 1470 1320 730 800 840 1130 690 900 1520 1050 1220 1400 1060 1420 560 1580 790 1240 1530 1010 510 540 1600 560 1520 1350 580 600 1600 1160 880 1320 720 1080 1400 620 1430 1560 800 1530 650 700 1400 1430 970 1230 1100 1370 1120 1290 1130 1010 1310

6 The point estimate of the mean monthly rental is,

d 1091.50

7 The variance of the sample mean is,

d 109,942.025

8 The margin of error for the 95% confidence interval is,

b 73.8

9 The upper end of the 95% interval estimate is,

c 1165.3

10 If you were asked to narrow the 95% margin of error to $25. How many apartments would you need to include in your sample? For planning value use $300.

a 620

Margin of error : 25= 1.96*331.575/sqrt(n)

n= 1.96^2*331.575^2/25^2 =675.76

nearest option 620.

Confidence Interval Estimate for the Mean
Data
Sample Standard Deviation	331.5750674
Sample variance	109942.025
Sample Mean	1091.5
Sample Size	80
Confidence Level	95%
Intermediate Calculations
Standard Error of the Mean	37.07121952
Degrees of Freedom	79
t Value	1.9905
Interval Half Width	73.7884
Confidence Interval
Interval Lower Limit	1017.71
Interval Upper Limit	1165.29