4.10. In-Service Teachers In their 2010 paper Linda Cooper and Felice Shore report on how 75 in-service teachers (grades 4-12) enrolled in a particular university's graduate program in mathematics education interpreted variability in different graphs [21]. Suppose our goal is to draw conclusions about all in-service, grades 4-12 teachers of mathematics in the U.S. (a) Describe the individuals under study. (b) What is the population of interest? (c) What is the sample size? (d) Why would a simple random sample be impossible? (e) What