Use county level data from $2010($Age$2010$ sheet$)$ and $2015($Age$2015$ sheet$)$ to

complete the highlighted cells in the $$Question $1$ worksheet. Describe how the

proportion of the population under $20$ and above $65$ has changed from $2010$ to from

$2015.$ Below is some guidance on how to proceed.

$$ Step $1$: Calculate the total population under $20$ and above $65$ for year $2010$ and

$2015.$

$$ Step $2$: Calculate percent change in population for the two age groups. Percent

change $=(2015$ data$-2010$ data$)/2010$ data.

$$ Step $3$: Calculate average, median, min, max, and standard deviation of percent

change for the two age groups.

$$ Step $4$: Draw histograms for percent changes in the two groups and determine

whether mean or median is a better measure of central tendency