Do you have a pictures you could insert
The correct answer would be option D.
No, it is not a valid inference because his classmates do not make up a random sample of the students in the school
The population represents all of the students in the school. Apart from his science class there can be students in arts class, music class, literature class and so on. He used convenience sampling by just surveying the students of his science class. The students in science class are those who are interested in science and related topics so these students will be more inclined towards watching a science program. Thus the survey of Johnny does not yield valid result and his inference is not valid.
Thus, option D is the correct answer.
The answer is A. If there are 3 thirds (1/3s) per yard and there are 6 yards, 3*6=18. Because the last cut will make two 1/3-yard segments, the answer is 17 cuts and not 18.
1 ton = 2,000 pounds, so 1 ton would of course weigh more than 388 pounds
