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Normal probability based on Z score

A company is interested in estimating the costs of lunch in their cafeteria. After surveying employees, the staff calculated that a 95% confidence interval for the mean amount of money spent for lunch over a period of six months is ($780, $920).

Now the organization is trying to write its report and considering the following interpretations. Comment on each.

a) 95% of all employees pay between $780 and $920 for lunch.
b) 95% of the sampled employees paid between $780 and $920 for lunch
c) We're 95% sure that employees in this sample averaged between $780 and $920 for lunch.
d) 95% of all samples of employees will have average lunch costs between $780 and $920
e) We're 95% sure that the average amount all employees pay for lunch is between $780 and $920

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Answer

The 95% confidence interval is related to the population parameter. The confidence interval can be interpreted as "With 95% confidence, we can claim that the average amount all employees pay for lunch is between $780 and $920."

a) ...

Solution Summary

Step by step method for calculating normal probability in different intervals is given in the answer.

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