A credit card company wanted to test whether how many of their customers charged
ID: 3323569 • Letter: A
Question
A credit card company wanted to test whether how many of their customers charged $500 ormore. The marketing department has pulled a sample of 500 customers from the same month last year and noted that the mean amount charged was $478.19 and the median amount was $216.48. The finance department says that the only relevant quantity is the proportion of customers who spend more than $500. If that proportion is not more than 25%, the program will lose money. Among the 500 customers, 158 of them charged $500 or more. you'd like to create the confidence interval to test whether the goal of 25% for all customers was met. If we use =0.025, the confidence interval for the true value of proportion is:
A)(0.256,0.336)
B)(0.243, 0.349)
C)(0.275, 0.357)
D)(0.263, 0.329)
E)(0.218, 0.282)
Explanation / Answer
The statistical software output for this problem is:
One sample proportion summary confidence interval:
p : Proportion of successes
Method: Standard-Wald
97.5% confidence interval results:
Hence,
Confidence interval will be:
(0.275, 0.357)
Option C is correct.
Proportion Count Total Sample Prop. Std. Err. L. Limit U. Limit p 158 500 0.316 0.020791537 0.27539779 0.35660221Related Questions
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