Question
In: Statistics and Probability
As part of an annual review of its accounts, a discount brokerage selects a random sample...
As part of an annual review of its accounts, a discount brokerage selects a random sample of 27 customers. Their accounts are reviewed for total account valuation, which showed a mean of $39,900, with a sample standard deviation of $8,300. (Use t Distribution Table.) What is a 99% confidence interval for the mean account valuation of the population of customers? (Round your answers to the nearest dollar amount.)
Solutions
Expert Solution
Solution :
Given that,
= 39900
s = 8,300
n = 27
Degrees of freedom = df = n - 1 = 27 - 1 = 26
At 99% confidence level the t is ,
= 1 - 99% = 1 - 0.99 = 0.01
/ 2 = 0.01 / 2 = 0.005
t
/2,df = t0.005,26 =2.779
Margin of error = E = t/2,df
* (s /
= 2.779 * (8,300 /
= 4439
Margin of error = 4439
The 99% confidence interval estimate of the population mean is,
- E < 
<
+ E
39900 - 4439 <
< 39900 + 4439
35461 <
< 44339
(35461, 44339)
orchestra answered 2 years agoRelated Solutions
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