The ADF test output for an observed time series appears below. Based on this output, is it likely that differencing once (a first-difference) would be useful?  Explain.

The Phillips-Perron test output for an observed time series appears below.  Based on this output, is it likely that differencing could be useful?  How many times?  Explain.   

Time series, cross-correlation, and ACF plots for series A and series B are below.  How much is the approximate lag between the two processes? 

What are the three most predominant fundamental frequencies suggested by the following periodogram?

The ADF test output for an observed time series appears below. Choose the best answer.

Briefly describe two ways in which commensal organisms in the gut benefit the human host.

Consider the following Ljung-Box test output: What does this test indicate about the residual process?  Explain.

All of the following describe mucous membranes, except: 

Match the transplant type with the correct definition.

Which immunoglobulin is used for the elimination of helminths?