John johnson used nonrandom sampling in his study of successful scientists. he knew most got excellent grades in high school and college, excelled in mathematics, and had a strong interest in science from a young age. for his study, he was interested in sampling those who were successful as adult scientists, but did poorly in high school, did average or worse in math classes, and showed little interest in science until they reached college or later in life. what type of sampling was he using?
