Question

#6

weekend before the final exam week. Her assistant took a random sample of 250 stadents The answer on "whether you visited campus bars on the weekend before the final exam week" from students in the sample is an example of A) a table of random numbers C) a categorical variable B) a continuous variable D) a discrete variable 3) 3) Which of the following is NOT a reason for the need for sampling? A) It is always more informative by investigating a sample than the entire population B) It is usually too time consuming to look at the whole population C) It is sometimes destructive to observe the entire population. D) It is usually too costly to study the whole population. 4) 4) Which of the following sampling methods is a probability sample? A) Convenience sample C) Stratified sample B) Judgment sample D) Quota sample 5) A study is under way in Yosemite National Forest to determine the adult height of American 5) pine trees. Specifically, the study is attempting to determine what factors aid a tree in reaching heights greater than 60 feet tall. It is estimated that the forest contains 25,000 adult American pines. The study involves collecting heights from 250 randomly selected adult American pine trees and analyzing the results. Identify the sample in the study A) The 25,000 adult American pine trees in the forest. B) All American pine trees, of any age, in the forest. C) All the adult American pine trees taller than 60 feet. D) The 250 randomly selected adult American pine trees shelf next to the cash 6) 6) To obtain a sample of 10 books in the store, the manager walked to the first register to pick the first 10 books on that shelf. This is an example of a A) simple random sample C) stratified sample B) systematic sample D) convenience sample 7) 7) Which of the following yields a systematic sample? A) The best 15 students, according to the opinion of the instructor, in a class are selected. B) All students in a class are divided into groups of 15. One student is randomly chosen from the 1st group, the remaining observations are every 15th student thereafter C) All students in a class are grouped according to their gender. A random sample of s is selected from the males and a separate random sample of 7 is drawn from the females. D) A random sample of 15 students is selected from a class without replacement

Answer 1

It is not simple random sampling as the first ten books are drawn from the shelf and hence is selection is not random.

It is not systematic as the first 10 books are selected and the first is not selected at random.

It is not stratified (if we assume there are more than one shelf) as the books from the shelf are not selected in random.

This is an example of convenience sampling as the shelf is chosen according to conveneince.