Description
Purpose of Assignment
The purpose of the assignment is to develop students' abilities in using datasets to apply the concepts of sampling distributions and confidence intervals to make management decisions.
Assignment Steps
Resources: Microsoft Excel®, The Payment Time Case Study, The Payment Time Case Data Set (Please create a text box for each within Microsoft Excel to complete this objective)
Review the Payment Time Case Study and Data Set.
Develop a summary in the text boxes including the following calculations and using the information to determine whether the new billing system has reduced the mean bill payment time:
- Assuming the standard deviation of the payment times for all payments is 4.2 days, construct a 95% confidence interval estimate to determine whether the new billing system was effective. State the interpretation of 95% confidence interval and state whether or not the billing system was effective.
- Using the 95% confidence interval, can we be 95% confident that µ ≤ 19.5 days?
- Using the 99% confidence interval, can we be 99% confident that µ ≤ 19.5 days?
- If the population mean payment time is 19.5 days, what is the probability of observing a sample mean payment time of 65 invoices less than or equal to 18.1077 days?
Click the Assignment Files tab to submit your Microsoft Excel data spreadsheet assignment.
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Explanation & Answer
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PayTime
22
19
16
18
13
16
29
17
15
23
18
21
16
10
16
22
17
25
15
21
20
16
15
19
18
15
22
16
24
20
17
14
14
19
15
27
12
17
25
13
17
16
13
a.
95% confidence interval
Confidence interval – mean
95%
18.1077
4.2
65
1.96
1.02
17.09
19.13
b.
confidence level
Mean
std. dev.
N
Z
margin of error
lower confidence limit
upper confidence limit
...