An economist used data from past years to find economic variables that are correlated with the growth rate in the U.S. Gross Domestic Product. The results are below: GDP growth rate (Pearson correlation GDP grow rate 1 interest rate .441 unemployment rate -.585 inflation rate .473), (Sig. 2-tailed interest rate .202 unemployment rate .075 inflation rate .167 ), (N GDP grow rate 10 interest rate 10 unemployment rate 10 inflation rate 10) According to the data, which other variable is causing the GDP growth rate to be what it is