Homework Answers
Ans:
a)
sample size,n=35
df=35-1=34
critical t value=tinv(0.05,34)=2.032
95% confidence interval for mean
=9.5+/-2.032*(2.5/sqrt(35))
=9.5+/-0.86
=(8.64, 10.36)
b)If sample size increases,standard error of mean decreases,so the margin of error decreases,hence width of the confidence interval decreases.
c)We are 95% confident that true mean reading time will lies between 8.64 and 10.36 minutes
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