The consumption function is one of the key relationships in economics, where consumption y depends on disposable income x. The accompanying data file shows quarterly data for these seasonally adjusted variables, measured in billions of dollars. Click here for the Excel Data File a-1. Estimate y = 60 + 61x+ E. (Round your answers to 2 decimal places.) + x Scatterplot of residual against time is shown below. 200 100 Residuals -100 - -200 .200 15 20 25-l Using the above plot, determine if there is a possibility of correlated observations. C" There is a possibility of positive serial correlation. C" There is a possibility of negative serial correlation. C" Serial correlation is unlikely. b. Discuss the consequences of serial correlation [correlated observations]. C" OLE estimators and their standard errors are both biased- C" OLE estimators are biased but their standard errors are unbiased. C" OLE estimators are unbiased but their standard errors are biased.