Call:
lm(formula = y ~ x)

Residuals:
     Min       1Q   Median       3Q      Max 
-0.02573 -0.02480 -0.01523  0.00059  0.45888 

Coefficients:
                      Estimate Std. Error t value            Pr(>|t|)    
(Intercept)           0.025734   0.002708   9.504 <0.0000000000000002 ***
xLow income          -0.014383   0.006095  -2.360              0.0186 *  
xLower middle income -0.010496   0.004901  -2.142              0.0326 *  
xNA                  -0.019254   0.009337  -2.062              0.0396 *  
xUpper middle income -0.008231   0.004526  -1.819              0.0694 .  
---
Signif. codes:  0 ‘***’ 0.001 ‘**’ 0.01 ‘*’ 0.05 ‘.’ 0.1 ‘ ’ 1

Residual standard error: 0.04729 on 707 degrees of freedom
Multiple R-squared:  0.01538,	Adjusted R-squared:  0.009808 
F-statistic: 2.761 on 4 and 707 DF,  p-value: 0.02687