Call:
lm(formula = y ~ x)

Residuals:
     Min       1Q   Median       3Q      Max 
-0.03968 -0.02767 -0.01585 -0.00473  0.41582 

Coefficients:
                      Estimate Std. Error t value            Pr(>|t|)    
(Intercept)           0.027682   0.003423   8.086 0.00000000000000267 ***
xLow income           0.012002   0.007706   1.558              0.1198    
xLower middle income -0.011821   0.006196  -1.908              0.0568 .  
xNA                  -0.021392   0.011806  -1.812              0.0704 .  
xUpper middle income -0.022936   0.005722  -4.008 0.00006768971174552 ***
---
Signif. codes:  0 ‘***’ 0.001 ‘**’ 0.01 ‘*’ 0.05 ‘.’ 0.1 ‘ ’ 1

Residual standard error: 0.05979 on 707 degrees of freedom
Multiple R-squared:  0.03588,	Adjusted R-squared:  0.03043 
F-statistic: 6.579 on 4 and 707 DF,  p-value: 0.00003357