Residual standard error: 13.5 on 2 degrees of freedom (5 observations deleted due to missingness) Multiple R-squared: 0.9999, Adjusted R-squared: 0.9989 F-statistic: 988.9 on 20 and 2 DF, p-value: 0.001011
为什么会有 5 observations deleted due to missingness 这个问题?有办法补救吗? 万分感谢