mean= 16,205.39 [Excel function used
-> AVERAGE]
sd= 2,353.857 [Excel function used ->
STDEV]
u= 10,000
n= 18.00 [Excel function used ->
COUNT]
alpha= 10%
critical value, t(a/2,n-1) = t(0.1/2,18-1) = 1.740
CI = mean +- t(a/2,n-1)*(sd/sqrt(n))
lower = 16205.3889 - 1.74*(2353.8572/sqrt(18)) =
5240.02
upper = 16205.3889 + 1.74*(2353.8572/sqrt(18)) =
17170.76
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