The frequency distribution was obtained using a class width of 0.5 for data on cigarette tax rates. Use the frequency distribution to approximate the population mean and population standard deviation. Compare these results to the actual mean mu equals=$1.635 and standard deviation sigma equals=$1.104.
1. What is population mean
2. What is standard deviation
Data:
Tax Rate | Lower Limit | Upper Limit | Frequency |
0.00-0.49 | 0 | 0.49 | 5 |
0.50-0.99 | 0.5 | 0.99 | 13 |
1.00-1.49 | 1 | 1.49 | 6 |
1.50-1.99 | 1.5 | 1.99 | 6 |
2.00-2.49 | 2 | 2.49 | 5 |
2.50-2.99 | 2.5 | 2.99 | 5 |
3.00-3.49 | 3 | 3.49 | 3 |
3.50-3.99 | 3.5 | 3.99 | 1 |
4.00-4.49 | 4 | 4.49 | 2 |
Class interval | Midpoint, x | Frequency, f | fx | fx² |
0 - 0.49 | 0.245 | 5 | 1.225 | 0.300125 |
0.5 - 0.99 | 0.745 | 13 | 9.685 | 7.215325 |
1 - 1.49 | 1.245 | 6 | 7.47 | 9.30015 |
1.5 - 1.99 | 1.745 | 6 | 10.47 | 18.27015 |
2 - 2.49 | 2.245 | 5 | 11.225 | 25.200125 |
2.5 - 2.99 | 2.745 | 5 | 13.725 | 37.675125 |
3 - 3.49 | 3.245 | 3 | 9.735 | 31.590075 |
3.5 - 3.99 | 3.745 | 1 | 3.745 | 14.025025 |
4 - 4.49 | 4.245 | 2 | 8.49 | 36.04005 |
Total | 46 | 75.77 | 179.61615 |
Mean, x̅ = ∑fx / n = 75.77/46 = 1.647
Standard deviation, s = √((∑fx² - (∑fx)²/n)/(n-1)) = √((179.6162 - 75.77²/46)/(46- 1)) = 1.1036
Get Answers For Free
Most questions answered within 1 hours.