If a data set of n=115 has a mean of 9.74 and a population standard deviation of 2.93, what is the 95% confidence interval?
1 Answer
Nov 2, 2015
We are 95% confidence that the population mean lies between
Explanation:
95% Confidence interval is -
#mu=barx+-(SE . z)#
# SE =sigma/sqrtn=2.93/sqrt115=2.93/10.72=0.27#
#z = 1.96#
Upper Limit:
#mu=9.74+(0.27 xx 1.96)#
#mu=9.74+0.53#
#mu=10.27#
Lower Limit:
#mu=9.74-(0.27 xx 1.96)#
#mu=9.74-0.53#
#mu=9.21#