A researcher selects his sample in this way. He paints numbers on ...

[nevelica]

A researcher selects his sample in this way. He paints numbers on 100 ping-pong balls, and he paints half of them blue and half of them green. He puts the blue half onto a large tray, and the green half of them onto another large tray.
 
  Then he mixes each group and trains his dog to bring 10 balls from each tray to him, gently and systematically, one at a time. What type of sample is this?
  a. Snowball
  b. Random
  c. Stratified random
  d. Systematic

Question 2

Good morning. You have been selected randomly by our marketing department because of your recent purchase of McCarthy's Natural Yogurt, several organic raw vegetables, and two types of tofu.
 
  As a woman with interest in safe and healthy products, we are asking you to participate in a brief telephone survey. The discerning student will detect an error in the above statement. What kind of a sampling is this?
  a. Random sampling
  b. Convenience sampling
  c. Purposive sampling
  d. Systematic sampling

[olivia_paige29]

Answer to Question 1

ANS: C
Stratified random sampling is used when the researcher knows some of the variables in the population that are critical to achieving representativeness. Variables commonly used for stratification are age, gender, ethnicity, socioeconomic status, diagnosis, geographical region, type of institution, type of care, care provider, and site of care. The dog has no agenda, and the balls are mixed. The dog chooses 10 balls from each stratum. The sample is stratified random.

Answer to Question 2

ANS: C
Marketing research now uses product profiling to identify what consumers buy which products. A sample based on profiling is a purposive sample: people are contacted because they possess a certain pattern of purchasing. This is also referred to as judgmental or selective sampling. If a sample is purposive, it is not random, convenience, or systematic.

[nevelica]

Excellent

[nothere]

Wow, this really help