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Chapter 8: Q.9 (page 477)

Construct a 90% confidence interval for the population mean time to complete the forms. State the confidence interval, sketch the graph and calculate the error bound.

Short Answer

Expert verified

The confidence interval isCl:(7.9441,8.4559).

Step by step solution

01

Given Information

90% confidence interval for the population mean time to complete the forms.

02

Explanation

Let's calculate the Margin of error by using the given formula:

Za2×σn

Place the values=Z0.102×2.2200=1.6449×2.2200=0.25588

Then we have to find the confidence interval by using the given formula:

X¯±Za2×σn

role="math" localid="1652508772667" Confidence Interval=8.2±Z0.102×2.2200=8.2±1.6449×2.2200=[7.944,8.455]

Therefore, the confidence interval Cl:(7.9441,8.4559).

The graph:

The error bound EBM=0.26.

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