A Researcher Wishes to Determine the Difference in Two Population

Multiple Choice

A researcher wishes to determine the difference in two population means.To do this, she randomly samples 9 items from each population and computes a 90% confidence interval.The sample from the first population produces a mean of 780 with a standard deviation of 240.The sample from the second population produces a mean of 890 with a standard deviation of 280.Assume that the values are normally distributed in each population and that the population variances are approximately equal.The critical t value used from the table for this is _______.

A) 1.860
B) 1.734
C) 1.746
D) 1.337
E) 2.342