Question

question #1 which of the following is not an example of an observational study? a researcher gives participants a medication and observes the side effects. a researcher takes a survey of college students majors. a researcher measures the flexibility of a group of students, then has them perform a set of stretches each day for a month. at the end of the month, the researcher measures the subjects flexibility again. none of the examples are observational studies. question #2 find the upper quartile for the following set of data: 168 169 172 174 175 176 177 179 181 184 178 79.5 72

Explanation:

Question #1

An observational study just observes and measures without interfering. Giving medication is an intervention, not just observation. Taking a survey and measuring flexibility without intervening are observational.

Step1: Arrange data in ascending order (already done).

168, 169, 172, 174, 175, 176, 177, 179, 181

Step2: Calculate position of upper quartile.

The formula for the position of the upper quartile ($Q_3$) for a data set of size $n$ is $Q_3$ position $=\frac{3(n + 1)}{4}$. Here $n=9$, so $Q_3$ position $=\frac{3\times(9 + 1)}{4}=\frac{3\times10}{4}=7.5$.

Step3: Find the upper quartile.

Since the position is 7.5, we take the average of the 7th and 8th ordered data values. The 7th value is 177 and the 8th value is 179. So $Q_3=\frac{177 + 179}{2}=178$.

Answer:

A. A researcher gives participants a medication and observes the side - effects.

Question #2