 Here is a data set that measures population growth rates in the US from 19101920
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 
 1918 would drag the average down from the median
 1918 would drag the average up from the median
 1918 would leave the average alone
What happened in 1918?
1.56. 1.48.

What can you say about the data from the median to q3 of the reaction times?
 The cell phone users did better because the data is more tightly clustered together
 The control group did better because the data is lower on the graph
 neither
 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?
 95
 5
 other
 Is there any way to know which intervals contain the true percentage and which ones don't?
 yes
 no
 Is there any way to know for sure if it is a representative sample?
 yes
 no
 How should we interpret the margin of error if the sample is very biased?
 It is still valid as is
 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.
 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.
 Sample A: a sample of n = 1000 from a population of 10 million
 Sample B: a sample of n = 2500 from a population of 200 million
 Sample C: a sample of n = 400 from a population of 50,000
 Write down in your own words what 95% confidence interval means.
 Write down in your own words what margin of error means.
defs