1. Here is a data set that measures population growth rates in the US from 1910-1920
 2.1 1.56 1.56 1.96 1.92 1.44 1.4 1.27 -0.06 1.26 1.85 1910 1911 1912 1913 1914 1915 1916 1917 1918 1919 1920
1. 1918 would drag the average down from the median
2. 1918 would drag the average up from the median
3. 1918 would leave the average alone

What happened in 1918?

1.56. 1.48.

2. What can you say about the data from the median to q3 of the reaction times?
1. The cell phone users did better because the data is more tightly clustered together
2. The control group did better because the data is lower on the graph
3. neither

3. Assume little to no bias and truly a random sample. If a polling company conducted 100 such polls with a 95% confidence interval, then about how many of them are likely to include the true population percentage?
1. 95
2. 5
3. other

4. Is there any way to know which intervals contain the true percentage and which ones don't?
1. yes
2. no

5. Is there any way to know for sure if it is a representative sample?
1. yes
2. no

6. How should we interpret the margin of error if the sample is very biased?
1. It is still valid as is
2. Garbage in garbage out, so the margin of error would not represent the entire population, although it would still be useful to interpret whatever biased sample it did represent.

7. In which of the following examples will the margin of error be the smallest? Assume each refers to a random sample that is not biased for a 95% confidence interval.
1. Sample A: a sample of n = 1000 from a population of 10 million
2. Sample B: a sample of n = 2500 from a population of 200 million
3. Sample C: a sample of n = 400 from a population of 50,000

8. Write down in your own words what 95% confidence interval means.
9. Write down in your own words what margin of error means.

defs