Question
In: Statistics and Probability
The proprietor of a boutique in New York wanted to determine the average age of his...
The proprietor of a boutique in New York wanted to determine the average age of his customers. A random sample of 53 customers revealed an average age of 28 years with a standard deviation of 4 years. Determine a 98% confidence interval estimate for the average age of all his customers.
Solutions
Expert Solution
Solution :
Given that,
Point estimate = sample mean = = 
28
Population standard deviation = 
= 4
Sample size = n =53
At 98% confidence level the z is ,
= 1 - 98% = 1 - 0.98 = 0.02
/ 2 = 0.02/ 2 = 0.01
Z/2
= Z0.01 = 2.326 ( Using z table )
Margin of error = E = Z/2
* ( 
/
= 2.326 * ( 4/
= 1.28
At 98% confidence interval is
- E < 
<
+ E
28 - 1.28 <
< 28 + 1.28
26.72 <
< 29.28
orchestra answered 2 years agoRelated Solutions
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