Business statistics Value of t and confidence interval

The U.S. Dairy Industry wants to estimate the mean yearly milk consumption. A sample of 13 people reveals the mean yearly consumption to be 58 gallons with a standard deviation of 18 gallons. 

(c)

For a 90 percent confidence interval, what is the value of t? (Round your answer to 3 decimal places.) Value of t is what _______________

(d)

Develop the 90 percent confidence interval for the population mean. (Round your answers to 3 decimal places.)   

 Confidence interval for the population mean is _______and ________.

Need both percents for this