Refer to the definition of simple random sample. determine whether each of the following is a simple random sample and a random sample.

a. a statistics class with 36 students is arranged so that there are 6 rows with 6 students in each row, and the rows are numbered from 1 through 6. a die is rolled and a sample consists of all students in the row corresponding to the outcome of the die.

b. for the same class described in part (a), the 36 student names are written on 36 individual index cards. the cards are shuµed and six names are drawn from the top.

c. for the same class described in part (a), the six youngest students are selected.