1. Find the critical value z/2 needed to construct a confidence interval with level 82%.

Round the answer to two decimal places.

2. A sample of size n= 70 is drawn from a normal population whose standard deviation is =6.2. The sample mean is x=46.21.

(a) Construct a 80% confidence interval for . Round the answer to at least two decimal places.

(b) If the population were not approximately normal, would the confidence interval constructed in part (a) be valid? Explain.

- The confidence interval constructed in part (a) ____ be valid since the sample size _____ large.