A random survey of 39national flags( with replacement between picks) from various countries is chosen. We are interested in the number of colors on each national flag that is chosen. The table below summarizes the results.

XFrequency11273184756

(a) What is the sample mean?

(b) What is the sample standard deviation?

(c) Find the associated t - score for an 80% confidence level.

(d) What is the error bound for means for a confidence level of 80%?

(e) Construct a 80% confidence interval for the true mean number of colors on a national flag.