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What type of sample was used in the following scenario:
Brad wants to know about the shopping habits of teenagers. He goes to the local mall and everytime he sees a teenager he asks them to fill out his survey. He spends one hour collecting responses on the top floor of the mall and one hour collecting responese on the bottom floor of the mall.
The correct anwer is a convenience sample because the sample is drawn from a population that is close, readily available, and convenient. The sample does not represent the shopping behaviors of all teenagers.
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Which of the following experiments has the least amount of bias?
The correct answer contains a control group and experimental group (placebo vs. therapeutic agent). Furthermore, it is randomized and double-blind.
The other incorrect choices introduce some form of bias - primarily selection bias in the two examples of surveys. The last example (the experiment with two experimental groups) does not have a control variable or placebo.
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A major chocolate company wants to test the effects of adding more sugar to their standard chocolate bar to see if customers enjoy it more.
They select 10 subjects to randomly participate in a taste test. They bring in samples of their original product, which is sold in tiny squares that says the company's name on them, and samples of the increased-sugar versions, which are plain chocolate squares of the same size. The company asked participants to taste both chocolates and rank how much they like them on a scale of 1 to 10.
Which of the following represents a possible source of bias in the study?
The presence of the company's name on the original sample may be a soure of bias. If people already have a preexisting opinion about the brand, they may rate that chocolate as better or worse based on those opinions rather than flavors.
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