A random sample of homeowners from Amarillo and Lubbock was asked to identify the primary source of heat for their homes. The following contingency table shows these results.
|
Source of Heat
|
Amarillo
|
Lubbock
|
|
Natural Gas
|
160
|
105
|
|
Electricity
|
115
|
45
|
|
Oil
|
20
|
10
|
|
Propane
|
15
|
10
|
|
Other
|
5
|
15
|
The probability that a randomly selected home from this sample uses electricity as its primary source of heat given that the home is located in Amarillo is ________.