Question

Public Utility Company	Rate (5 CCF)
Orlando Utilities Commission	$10.48
Memphis Light, Gas and Water	$9.18
Central Arkansas Water	$11.80
City of Phoenix Water System	$6.50
City of Lincoln Water System	$12.42
San Antonio Water System	$14.53
Salt Lake City Public Utilities	$15.56
Nashville Metro Water Services	$10.12
City of Dover Water System	$14.50
Lakeland Electric	$16.18
Huntsville Utilities	$17.60
Omaha Metropolitan Utilities District	$19.18
Jacksonville Electric Authority	$17.98
City of Dallas Water System	$12.85
City of St. Louis Water System	$16.80
Charleston Water System	$17.35
City of Clewiston Water System	$15.64
Springfield (IL) City Water, Light and Power	$14.80
City Of Milwaukee Water System	$18.91
Detroit Sewerage and Water Department	$17.99
City of Charlotte Water System	$14.90
Louisville Water Company	$18.42
City of Jackson (MS) Water System	$16.05
Las Vegas Valley Water District	$26.85
City of Columbus OH Water System	$22.32
City of Oklahoma City - Utilities	$22.76
Jackson TN Energy Authority	$20.98
Knoxville Utilities Board	$23.45
New York City Water Board	$19.05
Reno Truckee Meadows Water Authority	$23.70
Chattanooga American Water Company	$19.26
Marietta Board of Lights & Water	$23.75
City Utilities of Springfield MO	$27.80
Indianapolis Citizens Energy Group	$27.05
City of Philadelphia Water System	$27.14
LA Sewerage and Water Board of New Orleans	$26.99
Boston Water and Sewer Commission	$24.68
Birmingham Water Works	$37.86
Austin Water	$26.51
City of Bellevue Water System	$39.01
City of Los Angeles Water System	$29.46
Peoria American Water	$41.65

Cost of Residential Water. On its municipal website, the city of Tulsa states that the rate it charges per 5 CCF of residential water is $21.62. How do the residential water rates of other U.S. public utilities compare to Tulsa's rate? The file ResidentialWater contains the rate per 5 CCF of residential water for 42 randomly selected U.S. cities.

a. Formulate hypotheses that can be used to determine whether the population mean rate per 5 CCF of residential water charged by U.S. public utilities differs from the $21.62 rate charged by Tulsa.

b. What is the p-value for your hypothesis test in part (a)?

c. At a = .05, can your null hypothesis be rejected? What is your conclusion?

d. Repeat the preceding hypothesis test using the critical value approach

Answer 1