23
Oman Insurance company took a random sample of 91 insurance claims paid out during a 1-year period. The resulting 95% confidence interval for the mean claim payment was (496 Dhs, 2,166 Dhs). Find the sample mean used when computing the interval. Round your answer to one decimal place.
The given information is
n=91
Confidence level is
α=0.05
from the confidence level the critical value is
zc= 1.96 (from statistical table)
To find the sample mean
The average of upper bound and lower bound of the confidence interval is
Average=(upper bound + lower bound)/2
=(2166+496)/2
=1331
The sample mean is 1331
The confidence interval form sample mean is
sample mean- lower bound=1331-496=835
and
upper bound -sample mean=2166-1331=835
Therefore,
sample mean is 1331