The Mean Gross Annual Incomes of Certified Tack Welders Are

question 105

Multiple Choice

The mean gross annual incomes of certified tack welders are normally distributed with the mean of $50,000 and a standard deviation of $4,000. The ship building association wishes to find out whether their tack welders earn more or less than $50,000 annually. The alternate hypothesis is that the mean is not $50,000.
If the level of significance is 0.10, what is the decision rule?

• A) Do not reject the null hypothesis if computed z lies between -1.65 and +1.65; otherwise, reject it
• B) Do not reject the null hypothesis if computed z is greater than 1.65; otherwise, reject it
• C) Do not reject the null hypothesis if computed z lies between -1.96 and +1.96; otherwise, reject it
• D) Reject the null hypothesis if computed z is below -1.96; otherwise, reject it
• E) None of these statements are true

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Definitions:

Kilogram

The base unit of mass in the International System of Units (SI), equivalent to the mass of the International Prototype of the Kilogram.

Kilometer

A unit of measurement equal to 1,000 meters, commonly used to measure distances.

Scientific Measurement

The process of obtaining a quantitative description of the properties of an object or event using instruments that adhere to a standard unit.

Estimate

A calculation or judgment made about a quantity or value when exact figures are not available or necessary.