STATS Midterm 1
Which of the following best describes a confounding variable? A variable you included in the study that did have an effect on the results. A variable you included in the study that had no effect on the results. All of the above. A variable you did not include in the study that may have had an effect on the results.
A variable you did not include in the study that may have had an effect on the results.
If you add 10 to every value of a data set, which of the following will also increase by 10? The median. The mean. Neither the median nor the mean will increase by 10. Both the median and mean will increase by 10.
Both the median and mean will increase by 10.
A flat histogram contains no variability whatsoever, according to our definition. True False
False
Changing the number of bins will never change the shape of a histogram. True False
False
A veterinarian collects data on 100 of his patients who come in every year for their annual check-ups. After 5 years, he compares the health status of the dogs to the cats. What type of study is this? Observational study Experiment.
Observational study
Which of the following is not one of the criteria for a good experiment? Select a random sample of individuals to participate Make comparisons Collect enough data Avoid or minimize bias
Select a random sample of individuals to participate
An experimenter compares a single brand of popcorn to see how much popcorn is popped using different time settings on the same microwave. The time settings are 1.5 minutes, 2 minutes, 2.5 minutes, and 3 minutes. In this situation, what is the factor? The microwave Time setting None of the above Brand of popcorn
Time setting
If there are a few very large values in a data set compared to the rest of the data, the mean will be larger than the median. True False
True
The mean is influenced by outliers (values that are much larger or much smaller than the rest of the data.) True False
True
Bob wants to do a telephone survey based on 100 people. Knowing that some people won't answer the phone, he selects a random sample of 200 names to be safe, so if someone isn't home, he can just call the next person on the list. He continue this way until he gets 100 responses. Will this sampling method create bias in Bob's data? Yes No
Yes
