95 Confidence Interval Formula T Test. The formula for the confidence interval for one population mean using the t distribution is. 20 30 samples have wider confidence intervals signifying greater imprecision.
When do you use confidence intervals. In this case the sample mean is 4 8. That means t n 1 2 05.
By working through countless examples of how to create confidence intervals for the difference of population means we will learn to recognize when to use a z test or t test and when to pool or not based on the sample data provided.
Of the statistic is in the unshaded region confidence intervals ttests p values p 11 31. The t value for 95 confidence with df 9 is t 2 262. The sample size n is 30. The formula for the confidence interval for one population mean using the t distribution is.
