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A study is observational when the researcher controls the behaviors of their subjects.

If a researcher is given a list of all 51,000 students that go to the university and each student has a 10% chance of being selected to participate in the study, what type of sampling has occurred?

A study is experimental when the researcher lets things happen naturally.

The 50th percentile is also know as what?

It is known that people in the USA spend on average 18 hours a day using electronic devices with a standard deviation of 5.8 hours. This data follows a normal distribution. What is the probability someone spends less than 13 hours using electronic devices a day? (round your answer to 4 decimals)

Select the best description of IQR.

A variable measured someone’s stress level, the variable has the following values: Not stressed at all, only a little stressed, stressed, and very stressed.   This variable type is [Answer1] This variable’s categorization is [Answer2]

It is known that people in the USA spend on average 17 hours a day using electronic devices with a standard deviation of 7 hours.  This data follows a normal distribution.  What is the probability someone spends exactly 17 hours using electronic devices a day? (round your answer to 4 decimals)

A variable measured the acidic/base balance of a liquid on the pH scale.  The pH scale exists on a range from 0 (extremely acidic) to 14 (extremely basic).   This variable type is [Answer1] This variable’s categorization is [Answer2]

It is known that incomes from the USA follow a normal distribution with a mean of $75,000 and a standard deviation of $12,000.  A researcher took a sample of 1000 people in the USA and obtained a sample mean of $57,000 with a standard deviation of $18,000.  What are the characteristics of the sampling distribution.