I have this model:
$$4F + 4.8N = a + bM +cP + dH$$
where $F$, $N$, $M$, $P$, $H$ are variables measured on a 7-point Likert's type scale and $b, c, d$, are coefficients and $a$ is a constant. I am using SPSS.
My question: $F$ and $N$ are both measured with 5 items. What formula do I use to compute them in SPSS?