If alpha is .05, then the z value for .05/2 is? 21. The t value with a 95% confidence and 24 degrees of freedom is 22. If an interval estimate is said to be constructed at the 90% confidence level, the confidence coefficient would be 23. A 95% confidence interval for a population mean is determined to be 100 to 120. If the confidence coefficient is reduced to 0.90, the interval for u