The following replicate molarities were obtained when standardizing a solution: 0.1067, 0.1071, 0.1066, and 0.1050. Can one of the results be discarded as due to accidental error at the 95%confidence level?

Can anyone help me with this? Please!

1. Consider a normal population distribution with the value of known?

a. What is the confidence level for the interval "X-bar "  

b. What is the confidence level for the interval "X-bar " ?

c. What value of in the Cl formula (7.5) results in a confidence level of 99.7%?

d. Answer the equation posed in part (c) for a confidence level of 75%? 

A simple random sample of size n is drawn from a population that is known to be normally distributed. The sample mean, x¯\bar{x}xˉ, is determined to be 104.3 and the sample standard deviation, s, is determined to be 15.9. (a) Construct the 90% confidence interval for the population mean if the sample size, n, is 15. (b) Construct the 90% confidence interval for the population mean if the sample size, n, is 25. How does increasing the sample size affect the width of the interval? (c) Construct the 95% confidence interval for the population mean if the sample size, n, is 15. Compare the results to those obtained in part (a). How does increasing the level of confidence affect the confidence interval? (d) Construct the 90% confidence interval for the population standard deviation if the sample size, n, is 15.�

confidence interval is obtained as:

a. point estimate ± critical value

b. point estimate ± standard error

c. point estimate ± margin of error