Question
In: Statistics and Probability
A simple random sample of 60 items resulted in a sample mean of 63. The population...
A simple random sample of 60 items resulted in a sample mean of 63. The population standard deviation is 15.
a. Compute the 95% confidence interval for the population mean (to 1 decimal).
b. Assume that the same sample mean was obtained from a sample of 120 items. Provide a 95% confidence interval for the population mean (to 2 decimals).
Solutions
Expert Solution
a) Sample size, n = 60
Sample mean, 
= 63
Standard deviation, 
= 15
At 95% confidence level the z is ,
=
1 - 95% = 1 - 0.95 = 0.05
/ 2 = 0.05 / 2 = 0.025
Z/2
= Z0.025 = 1.960
At 95% confidence interval estimate of the population mean is,
- E < 
<
+ E
which is the required 95%
confidence interval for population mean.
orchestra answered 1 year agoRelated Solutions
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