In: Statistics and Probability
A random sample of professional wrestlers was obtained, and the annual salary (in dollars) for each was recorded. The summary statistics were x = 45,500 and n = 17. Assume the distribution of annual salary is normal with o = 8,500.
(a) Find a 90% confidence interval for the true mean annual salary for all professional wrestlers (in dollars). (Round your answers to four decimal places.)
(______________ , ______________) kg
Given that,
Point estimate = sample mean =
= 45500
Population standard deviation =
= 8500
Sample size = n =17
At 90% confidence level
= 1 - 90%
= 1 - 0.90 =0.10
/2
= 0.05
Z/2
= Z0.05 = 1.645
Margin of error = E = Z/2
* (
/n)
= 1.645* ( 8500 / 17
)
= 3391.2544
At 90% confidence interval estimate of the population mean
is,
- E <
<
+ E
45500- 3391.2544 <
< 45500+ 3391.2544
42108.7456 <
< 48891.2544
( 42108.7456 , 48891.2544)