A researcher is interested in finding a 95% confidence interval for the mean number of times per day that college students text. The study included 139 students who averaged 30.2 texts per day. The standard deviation was 16.3 texts. Round answers to 3 decimal places where possible.

a. To compute the confidence interval use a ? z, t distribution.

b. With95% confidence the population mean number of texts per day is between and texts.

c.If many groups of 139 randomly selected members are studied, then a different confidence interval would be produced from each group. About percent of these confidence intervals will contain the true population number of texts per day and about percent will not contain the true population mean number of texts per day.