Researchers studying the acquisition of pronunciati on often compare measurements made on the recorded speech of adults and children. One variable of interest is called "voice onset time" (VOT), the...

Extracted text: Researchers studying the acquisition of pronunciati on often compare measurements made on the recorded speech of adults and children. One variable of interest is called "voice onset time" (VOT), the length of time between the release of a consonant sound (such as "p") and the beginning of the following vowel (such as the "a" in "pat"). For speakers of English, this short time lag can be heard as a period of breathiness between the consonant and the vowel. Here are the results for some randomly selected 4-year-old chil dren and adults asked to pronounce the word "pat." VOT is measured in milliseconds. Children 10 60.67 39.89 Adults 88.17 24.74 (a) What additional information would you need to confirm that the conditions for this test have been met? (b) Construct and interpret a 95% confidence interval for the true difference in the mean VOT for all 4-year-old children and adults. Assume the condition discussed in part (a) has been met.