Sound it out:Phonics is an instructional method in which children are taught to connect sounds with letters or groups of letters. A sample of

141 first-graderswho were learning English were asked to identify as many letter sounds as possible in a period of one minute. The average number of letter sounds identified was 34.09 with a standard deviation of 23.44.

Part 1 of 2

(a) Construct a 90%

confidence interval for the mean number of letter sounds identified in one minute. Round the answers to at least two decimal places.