The Mean Amount of Gasoline and Services Charged by Key

question 124

Multiple Choice

The mean amount of gasoline and services charged by Key Refining Company credit customers is $70 per month. The distribution of amounts spent is approximately normal with a standard deviation of
$10) What is the probability of selecting a credit card customer at random and finding the customer charged between $70 and $83?

• A) 0.1962
• B) 0.4032
• C) 0.3413
• D) 0.4750
• E) None of the choices are correct

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Definitions:

Degrees of Freedom

The number of independent values or quantities which can be assigned to a statistical distribution or to a system without violating any constraint.

Contingency Table

A tabular method to represent and analyze the relationship between two or more categorical variables, showing the distribution of one variable across levels of the other variable(s).

Chi-square Test of Independence

A statistical analysis aimed at identifying a meaningful relationship between two variables that can be categorized.

Quantitative Variables

Variables that represent measurable quantities and can take on numerical values.