2. str(iris)
## 'data.frame': 150 obs. of 5 variables:
## $ Sepal.Length: num 5.1 4.9 4.7 4.6 5 5.4 4.6 5 4.4 4.9 ...
## $ Sepal.Width : num 3.5 3 3.2 3.1 3.6 3.9 3.4 3.4 2.9 3.1 ...
## $ Petal.Length: num 1.4 1.4 1.3 1.5 1.4 1.7 1.4 1.5 1.4 1.5 ...
## $ Petal.Width : num 0.2 0.2 0.2 0.2 0.2 0.4 0.3 0.2 0.2 0.1 ...
## $ Species : Factor w/ 3 levels "setosa","versicolor",..: 1 1 1 1 1 1 1 1 1 1 ...
3. summary(iris)
## Sepal.Length Sepal.Width Petal.Length Petal.Width
## Min. :4.300 Min. :2.000 Min. :1.000 Min. :0.100
## 1st Qu.:5.100 1st Qu.:2.800 1st Qu.:1.600 1st Qu.:0.300
## Median :5.800 Median :3.000 Median :4.350 Median :1.300
## Mean :5.843 Mean :3.057 Mean :3.758 Mean :1.199
## 3rd Qu.:6.400 3rd Qu.:3.300 3rd Qu.:5.100 3rd Qu.:1.800
## Max. :7.900 Max. :4.400 Max. :6.900 Max. :2.500
## Species
## setosa :50
## versicolor:50
## virginica :50
##
##
##
4. summary(lm(iris[,1]~.,data=iris[, -5]))
summary(lm(iris[,1]~.,data=iris[, -5]))
## Warning in summary.lm(lm(iris[, 1] ~ ., data = iris[, -5])): essentially
## perfect fit: summary may be unreliable
##
## Call:
## lm(formula = iris[, 1] ~ ., data = iris[, -5])
##
## Residuals:
## Min 1Q Median 3Q Max
## -2.330e-15 -1.857e-17 1.444e-17 4.207e-17 1.847e-16
##
## Coefficients:
## Estimate Std. Error t value Pr(>|t|)
## (Intercept) -2.595e-15 1.875e-16 -1.384e+01 <2e-16 ***
## Sepal.Length 1.000e+00 5.277e-17 1.895e+16 <2e-16 ***
## Sepal.Width 4.253e-17 5.464e-17 7.780e-01 0.438
## Petal.Length 3.162e-17 5.204e-17 6.080e-01 0.544
## Petal.Width -1.698e-17 8.646e-17 -1.960e-01 0.845
## ---
## Signif. codes: 0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
##
## Residual standard error: 2.006e-16 on 145 degrees of freedom
## Multiple R-squared: 1, Adjusted R-squared: 1
## F-statistic: 6.35e+32 on 4 and 145 DF, p-value: < 2.2e-16