A random sample of 20 items is drawn from a population whose standard deviation is unknown. The sample mean isx

x

= 930 and the sample standard deviation iss= 5. UseAppendix Dto find the values of Student'st.

(a)Construct an interval estimate ofwith 98% confidence.(Round your answers to 3 decimal places.)

The 98% confidence interval is fromto

(b)Construct an interval estimate ofwith 98% confidence, assuming thats= 10.(Round your answers to 3 decimal places.)

The 98% confidence interval is fromto

(c)Construct an interval estimate ofwith 98% confidence, assuming thats= 20.(Round your answers to 3 decimal places.)

The 98% confidence interval is fromto