Question
In: Statistics and Probability
A random sample of 10 batteries is obtained. It is determined that the mean life is...
A random sample of 10 batteries is obtained. It is determined that the mean life is 5 hours, with a sample standard deviation of 1 hour.
A)Find the 95% confidence interval (CI) for the unknown mean of the population.
B)Interpret the meaning of the confidence interval.
Solutions
Expert Solution
Solution :
Given that,
= 5
s =1
n = Degrees of freedom = df = n - 1 =10 - 1 = 9
At 95% confidence level the t is ,
= 1 - 95% = 1 - 0.95 = 0.05
/
2= 0.05 / 2 = 0.025
t
/2,df = t0.025,9 =2.262 ( using student t
table)
Margin of error = E = t/2,df
* (s /
= 2.262 * ( 1/
= 0.715
The 95% confidence interval estimate of the population mean is,
- E < 
<
+ E
5 -0.715 <
< 5+ 0.715
4.285 <
< 5.715
b sample mean lies between these confidence bound
lower bound 4.285
uppwer bound 5.715
orchestra answered 2 years agoRelated Solutions
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