biomass
23. Biomass Power Plants. Power plants around the country are retooling in order to consume biomass instead of or in addition to coal. The table contains a random sample of nine such power plants and the amount of energy generated in megawatts (MW) in 2014.16 The normality was checked in the Section 8.4 exercises. Test whether the population standard deviation differs from 25 MW, using level of significance .
| Company | Location | Capacity (MW) |
|---|---|---|
| Hoge Lumber Co. | New Knoxville, Ohio |
3.7 |
| Evergreen Clean Energy | Eagle, CO | 12.0 |
| GreenHunter Energy | Grapevine, TX | 18.5 |
| Covanta Energy Corporation |
Niagara Falls, NY | 30.0 |
| Northwest Energy Systems Co. |
Warm Springs, OR |
37.0 |
| Riverstone Holdings | Kenansville, NC | 44.1 |
| Lee County Solid Waste Authority |
Ft. Myers, FL | 57.0 |
| Energy Investor Funds | Detroit, MI | 68.0 |
| Dominion Virginia Power | Hurt, VA | 83.0 |
9.6.23
Step 1
Step 2 and . Therefore we reject if or .
Step 3
Step 4 is not and is not , so we do not reject . There is insufficient evidence at level of significance that the population standard deviation differs from 25 MW.