A simple tandem sample of size n is dawn from a population that is normally dist
ID: 3253206 • Letter: A
Question
A simple tandem sample of size n is dawn from a population that is normally distributed. The sample mean, x is found to be 111, and the sample standard deviation, s is found to be 10. (a) Construct an 80% confidence interval about mu if the sample size, n is 27. (b) Construct an 80% confidence interval about mu if the sample size, n is 20. (c) Construct a 70% confidence interval about mu if the sample size, n is 27. (d) Could we have the confidence intervals in parts (a) - (c) if the population had not been normally distributed? (a) Construct an 80% confidence interval about mu if the sample size, n is27. Lower bound Upper bound (Use ascending order Round to one decimal place as needed.)Explanation / Answer
The statistical software outputs for this problem are:
One sample T confidence interval:
: Mean of population
80% confidence interval results:
80% confidence interval results:
70% confidence interval results:
Hence,
a) Lower bound = 108.5
Upper bound = 113.5
b) Lower bound = 108.0
Upper bound = 114.0
c) Lower bound = 109.0
Upper bound = 113.0
d) No, because the sample sizes are less than 30.
Mean Sample Mean Std. Err. DF L. Limit U. Limit 111 1.9245009 26 108.46934 113.53066