[R] Differences in estimates calculated in R and SPSS

[Katja Walentowitz]

Hi,

I am writing a term paper about linear regression and analysis of variance in R and SPSS.

I am a bit confused because I get different estimates for the regression coefficients from R and SPSS. 
Does anyone have an explanation for this?  As I am not so experienced in data analysis, I don't know why this happens. 

Thank you for helping,
Katja