A random sample of 20 purchases showed the amounts in the table​ (in $). The mean is ​$49.30 and the standard deviation is ​$21.86. ​a) Construct a ​98% confidence interval for the mean purchases of all​ customers, assuming that the assumptions and conditions for the confidence interval have been met. ​b) How large is the margin of​ error? ​c) How would the confidence interval change if you had assumed that the population standard deviation was known to be ​$22?

College Algebra (MindTap Course List)
12th Edition
ISBN:9781305652231
Author:R. David Gustafson, Jeff Hughes
Publisher:R. David Gustafson, Jeff Hughes
Chapter8: Sequences, Series, And Probability
Section8.CR: Chapter Review
Problem 37E: Find the positive geometric mean between 4 and 64.
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A random sample of 20 purchases showed the amounts in the table​ (in $). The mean is ​$49.30 and the standard deviation is ​$21.86.
​a) Construct a ​98% confidence interval for the mean purchases of all​ customers, assuming that the assumptions and conditions for the confidence interval have been met.
​b) How large is the margin of​ error?
​c) How would the confidence interval change if you had assumed that the population standard deviation was known to be ​$22?

 

 

80.07 46.00 33.65
40.73 28.05
73.99
81.14 49.00 74.42
22.45
50.49
35.50
6.36
31.25
78.32
44.99 71.76 58.78
25.95 53.05
Transcribed Image Text:80.07 46.00 33.65 40.73 28.05 73.99 81.14 49.00 74.42 22.45 50.49 35.50 6.36 31.25 78.32 44.99 71.76 58.78 25.95 53.05
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