Call:
lm(formula = y ~ x)

Residuals:
     Min       1Q   Median       3Q      Max 
-0.01618 -0.01616 -0.01134 -0.00309  0.71470 

Coefficients:
                      Estimate Std. Error t value  Pr(>|t|)    
(Intercept)           0.016178   0.003446   4.695 0.0000032 ***
xLow income          -0.013086   0.007756  -1.687     0.092 .  
xLower middle income -0.003667   0.006237  -0.588     0.557    
xNA                  -0.016113   0.011883  -1.356     0.176    
xUpper middle income -0.009689   0.005760  -1.682     0.093 .  
---
Signif. codes:  0 ‘***’ 0.001 ‘**’ 0.01 ‘*’ 0.05 ‘.’ 0.1 ‘ ’ 1

Residual standard error: 0.06018 on 707 degrees of freedom
Multiple R-squared:  0.007737,	Adjusted R-squared:  0.002123 
F-statistic: 1.378 on 4 and 707 DF,  p-value: 0.2398