The table below shows the unemployment rate and the available workforce for three counties in northwest Pennsylvania for May 2010 and April 2013.

a. In May 2010, the national unemployment rate was 9.7%. For May 2010, compute a simple average unemployment index for the region using the national unemployment rate as the base. Interpret the simple average index.
b. In April 2013, the national unemployment rate was 7.6%. For April 2013, compute a simple average unemployment index for the region using the national unemployment rate as the base. Interpret the simple average index.
c. Use the data for this region of northwest Pennsylvania to create a weighted unemployment index using the Laspeyres method. Use May 2010 as the base period. Interpret theindex.