Strict stationarity implies

You compute the AIC for AR(p) models for lag lengths p=0,1,2: AIC(0) = -3.4, AIC(1) = -3.5, AIC(2) = -3.4. According to AIC the best among these models is

Consider the question, “What is the mean daily return (%) of a certain stock on the day after the overall market (S&P 500 index) increases, minus the mean daily stock return the day after an overall decrease?” This question primarily concerns

The first (top) forecast is clearly better because

Consider a strictly stationary time series with 0.8 first autocorrelation and mean zero.  One way to conceptualize this is:A.  If we could observe the series infinitely far into the future and/or past, we’d see that positive values tend to follow positive values and that negative values tend to follow negative values.B.  If we could observe an infinite number of universes with the same process generating the time series, then looking across the universes we’d see that positive values tend to follow positive values and that negative values tend to follow negative values.

What is the correct function of a lymph node?

Which of the following is a chemical mediator that promotes inflammation?

 Which of the following is an example of naturally acquired passive immunity?

Blood leaving the right ventricle would flow through which of the following structures in order?

Which type of T cell directly destroys infected or abnormal cells?