When testing for the differences between the means of two independent populations, only a two-tailed test can be used

Each member of a workgroup accesses data located on a database server

Indicate whether the statement is true or false

A cell phone service provider has selected a random sample of 20 of its customers in an effort to estimate the mean number of minutes used per day

The results of the sample included a sample mean of 34.5 minutes and a sample standard deviation equal to 11.5 minutes. Based on this information, and using a 95 percent confidence level: A) the critical value is z = 1.96 B) the critical value is z = 1.645 C) the critical value is t = 2.093 D) The critical value can't be determined without knowing the margin of error.