Answer:
sample size (n)=18,
sample mean () = 3390
sample standard deviation (s) = 179.8
a)
c=95%
formula for confidence interval is
Where is the t critical value for c=95% and
df = n-1 = 18-1 = 17
using t table we get critical value as
= 2.110
3390 − 89.412 < < 3390 + 89.412
3300.588 < < 3479.412
Thus we get 95% confidence interval as (3300.588 , 3479.412)
b)
By increasing the sample size (n) we can reduce the margin of error,
because increasing the sample size reduces the standard error. which results into the reduced margin of error
. A Simple random sample of 18 recent birth records at the local hospital was taken....
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