Section 33 Estimates

33.1 Estimates: Effects

\[ \large fm \leftarrow lm(SBP \sim Group, \space data=BP) \]

\[ \large summary(fm) \]


Call:
lm(formula = SBP ~ Group, data = BP)

Residuals:
    Min      1Q  Median      3Q     Max 
-19.093  -5.101   0.146   5.960  13.772 

Coefficients:
            Estimate Std. Error t value Pr(>|t|)    
(Intercept)   98.938      2.601  38.041  < 2e-16 ***
GroupB         8.352      3.678   2.271   0.0292 *  
GroupC         4.730      3.678   1.286   0.2067    
GroupD        16.855      3.678   4.582 5.34e-05 ***
---
Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1

Residual standard error: 8.225 on 36 degrees of freedom
Multiple R-squared:  0.3846,    Adjusted R-squared:  0.3333 
F-statistic: 7.498 on 3 and 36 DF,  p-value: 0.0005059

	Estimate	Std. Error	t value	Pr(>\|t\|)
(Intercept)	98.938	2.6008	38.0407	0.0000
GroupB	8.352	3.6782	2.2707	0.0292
GroupC	4.730	3.6782	1.2860	0.2067
GroupD	16.855	3.6782	4.5825	0.0001

33.2 Estimates: Means

\[ \large fm1 \leftarrow lm(SBP \sim -1 + Group, \space data=BP) \]

\[ \large summary(fm1) \]


Call:
lm(formula = SBP ~ -1 + Group, data = BP)

Residuals:
    Min      1Q  Median      3Q     Max 
-19.093  -5.101   0.146   5.960  13.772 

Coefficients:
       Estimate Std. Error t value Pr(>|t|)    
GroupA   98.938      2.601   38.04   <2e-16 ***
GroupB  107.290      2.601   41.25   <2e-16 ***
GroupC  103.668      2.601   39.86   <2e-16 ***
GroupD  115.793      2.601   44.52   <2e-16 ***
---
Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1

Residual standard error: 8.225 on 36 degrees of freedom
Multiple R-squared:  0.9947,    Adjusted R-squared:  0.9941 
F-statistic:  1680 on 4 and 36 DF,  p-value: < 2.2e-16

	Estimate	Std. Error	t value
GroupA	98.938	2.6008	38.0407
GroupB	107.290	2.6008	41.2520
GroupC	103.668	2.6008	39.8593
GroupD	115.793	2.6008	44.5213

plot.design(SBP ~ Group, data=BP)