Sarah wanted to review what others thought of a new video game she was interested in before
she purchased it. She noticed that on the website from a large online retailer, the game received
an overall rating of 4.5 sta
...
Sarah wanted to review what others thought of a new video game she was interested in before
she purchased it. She noticed that on the website from a large online retailer, the game received
an overall rating of 4.5 stars.
Which of the following is an example of selection bias?
Sarah reviews several different star ratings to get a sense of what all users thought about the
game.
Sarah only reads the 5-star reviews to make a decision on whether or not to buy the game.
Each person who owned the game gave it a rating.
People who owned the game were able to choose whether or not they would rate it.
RATIONALE
If Sarah only chose reviewers who gave a 5-star review, she is not selecting a group of people
who represent all different opinions about the game.
CONCEPT
Issues with Performing Experiments
2
On a recent news report, Taylor heard that, on average, most Americans get six hours of sleep
each night. The report continued by stating that in Taylor's state, Minnesota, residents were
actually getting an average of eight hours of sleep each night.
Considering the information in this news story, which of the following correctly describes a
parameter?
The average number of hours people sleep nationally
The total number of people who participated in the study
The average number of hours residents of Minnesota sleep
The total number of people from Minnesota who participated in the study
RATIONALE
The parameter represents the value of the variable of interest of the population. In this case, the
population is all people nationally, so their average number of hours of sleep is the parameter.
CONCEPT
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