The Mean Annual Incomes of Certified Welders Are Normally Distributed

question 11

Multiple Choice

The mean annual incomes of certified welders are normally distributed with the mean of $50,000 and a population standard deviation of $2,000. The ship building association wishes to find out whether their welders earn more or less than $50,000 annually. A sample of 100 welders is taken and the mean annual income of the sample is $50,350. If the level of significance is 0.05,what conclusion should be drawn?

• A)Do not reject the null hypothesis as the test statistic is less than the critical value of z.
• B)Do not reject the null hypothesis as the test statistic is less than the critical value of t.
• C)Reject the null hypothesis as the test statistic is greater than the critical value of t.
• D)Reject the null hypothesis as the test statistic is greater than the critical value of z.

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Definitions:

Standard Time

A set duration assigned for completing a given task, based on average time studies and used for planning and scheduling work.

Revised Activity

An activity or task that has been modified or updated to improve efficiency or effectiveness.

Original Activity

An initial or primary action that serves as the basis or starting point for subsequent processes or operations.

TMU

Time Measurement Unit, a standard used in work measurement and time study techniques to quantify the time required for specific tasks.