# Dummy variables in equation? [closed]

I have a model equation with 10 year and 10 industry dummies. In equation, it will look like this: year$$_1$$ year$$_2$$ ... year$$_10$$ ind$$_1$$ ind$$_2$$ .... ind$$_{10}$$ which is too long to write out. Is there any other way I can write it? maybe with summation notation?

Lev = β0 + β1 PROF + β2 SIZE + β3 TANG + β4GROWTH +β5 LIQ +β6 year1 + β7 year2+ β8 year3 +β9year4 +β10 year5 +β11year6 +β12year7 +β13year8 +β14year9 +β15year10 +β16ind1 +β17ind2 +β18ind3 +β19ind4 +β20 ind5 +β21ind6 +β22ind7 +β23ind8 +β24ind9 +β25ind10

## closed as unclear what you're asking by Nick Cox, kjetil b halvorsen, mdewey, Tim♦Feb 18 at 12:41

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• If people expect to see each coefficient, then that's what's expected, and not otherwise. Not clear to me what else you're asking, as there's some unstated context of assignment/thesis or dissertation/paper for journal that influences or determines what's expected. – Nick Cox Feb 18 at 9:17
• Lev = β0 + β1 PROF + β2 SIZE + β3 TANG + β4GROWTH +β5 LIQ +β6 year1 + β7 year2+ β8 year3 +β9year4 +β10 year5 +β11year6 +β12year7 +β13year8 +β14year9 +β15year10 +β16ind1 +β12ind2 +β13ind3 +β14ind4 +β15 ind5 +β16ind6 +β17ind7 +β18ind8 +β19ind9 +β20ind10 Ths equation is quite long, so I would like to know how can I show it in a simpler form if possible – Winter T Feb 18 at 9:22
• Maybe a plot would be nicer. – user2974951 Feb 18 at 9:51
• Still, no context. Just possibly, you might be expected to be explicit to show your understanding. As $\beta_{12}$ to $\beta_{16}$ appear twice here, that might be a little shaky. OTOH, no one is much interested in notation being defined if it is never used thereafter. – Nick Cox Feb 18 at 11:19