# Formula for computing variable from Likert-type scale

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?

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Somewhere somehow someone must have stated something about how F and N are derived. Did you have the original documentation about this model? And if so, post it here or we may not be able to give any concrete answer. – Penguin_Knight May 21 '13 at 14:30
As above. Not meaning to be facetious, but it's hard to think of an answer beyond stating that you need to know the values of a, b, c, d. Also, the formula is presumably the same for any other software. Why single out SPSS? You may well be using it, but on the face of it, this isn't a question about using SPSS. (If it is, it belongs on Stack Overflow or an SPSS list.) – Nick Cox May 21 '13 at 14:39