The Average Monthly Electric Bill of a Random Sample of 256

question 20

Short Answer

The average monthly electric bill of a random sample of 256 residents of a city is $90 with a standard deviation of $24.
a.Construct a 90% confidence interval for the mean monthly electric bills of all residents.
b.Construct a 95% confidence interval for the mean monthly electric bills of all residents.

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Definitions:

Marginal Cost

The increase in costs resulting from the manufacturing of one extra good or service.

Dominant Price Leader

A firm that has the largest market share within an industry and whose pricing decisions are often followed by other firms in the market.

Monopolist

An entity, individual, or company that is the sole supplier of a particular commodity or service in a market, often resulting in the power to control prices and market conditions.

Market Demand

The aggregate amount of a product or service that every customer in a market is prepared and able to buy at different price levels.