A simple random sample of 60 items resulted in a sample mean of 96. The population standard deviation is 16.
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).
( , )
c. What is the effect of a larger sample size on the margin of error, does it increase, decrease,stays the same, or it cannot be determined?
NOTE: I don't know if it is right.
a. I got (194.2,202.3)
b. I got (137.35, 143.08)
c. It decrease
4 answers
Only c is correct
Can you help me please?
thanks
thanks
I did not know how to do it.
A)
z = 1.96
n = 60
x-bar = 96
S = 16
SE = σ/√n = 16/√60
xbar ± z*s/√n
96 ± 4.048
( 92.0, 100.0)
B)
z = 1.96
SE = σ/√n = 16/√120
96 - 2.867, 96 + 2.867
(93.1, 98.9)
z = 1.96
n = 60
x-bar = 96
S = 16
SE = σ/√n = 16/√60
xbar ± z*s/√n
96 ± 4.048
( 92.0, 100.0)
B)
z = 1.96
SE = σ/√n = 16/√120
96 - 2.867, 96 + 2.867
(93.1, 98.9)
3 answers