A camp director is interested in the mean number of letters each child sends during his or her camp session. The population standard deviation is known to be 2.2. A survey of 20 campers is taken. The mean from the sample is 7.3 with a sample standard deviation of 2.9. SEE ATTACHMENT FOR QUESTIONS

Construct a 90% confidence interval for the population mean number of letters campers send home (i) )State the confidence interval. (Round your answers to two decimal places.) (:l E) (ii) Sketch the graph. (Round your answers to two decimal places.) 3- E C,L,=_ %=: (iii) Calculate the error bound (Round your answer to two decimal places.) E