“…In brief, an AR model of a variable presents a temporary dependence of previous values of the same variable, so in order to forecast the value of an AR variable, we only need to know the value of the previous record of that variable for any given subject. To describe the autoregressive model of salivary behaviour, if we suppose that a person’s sAA level at a certain time is a function of the amount of sAA shown by that same person in the previous p hr ( sAA j , t = f(sAA j , t-1 , sAA j , t-2 , … , sAAs j , t-p ), then where sAA is the value of the variable sAA for participant j at hr t ; subscript j represents each participant ( j : 1 , 2 , … , 19 ); t is the moment of measurement, thus if we consider a value of sAA for a person j at a particular hr t (or sAA j , t ), then the sAA value of this person j at the previous hr ( t-1) will be sAA j , t-1 , and so on until sAA j , t-p , p being the number of significant explanatory lags of sAA; the terms b and e are as in Eqs 1 and 2, though obviously they are different coefficients in the two equations because their statistical relationships are different; evidently, b 0j in Eq 3 is multilevel, its formulation being as in Eq 2 [15, 25, 28, 45–50].…”