Ejemplo resistencia de cajas de cartón

Se compararon la resistencia a la compresión (lb.) de cuatro tipos distintos de cajas.

Tipo Resistencia
A 655.5 788.3 734.3 721.4 679.1 699.4
B 789.2 772.5 786.9 686.1 732.1 774.8
C 737.1 639.0 696.3 671.7 717.2 727.1
D 535.1 628.7 542.4 559.9 586.9 520.0 
## 
## Attaching package: 'dplyr'
## The following objects are masked from 'package:stats':
## 
##     filter, lag
## The following objects are masked from 'package:base':
## 
##     intersect, setdiff, setequal, union
## # A tibble: 4 × 3
##     tipo     mean       sd
##   <fctr>    <dbl>    <dbl>
## 1      A 713.0000 46.55053
## 2      B 756.9333 40.33543
## 3      C 698.0667 37.20165
## 4      D 562.1667 39.86205

## 
## Call:
## lm(formula = resistencia ~ tipo, data = dat)
## 
## Residuals:
##     Min      1Q  Median      3Q     Max 
## -70.833 -26.542   3.317  25.808  75.300 
## 
## Coefficients:
##             Estimate Std. Error t value Pr(>|t|)
## (Intercept)   713.00      16.79  42.462  < 2e-16
## tipoB          43.93      23.75   1.850   0.0791
## tipoC         -14.93      23.75  -0.629   0.5366
## tipoD        -150.83      23.75  -6.352 3.37e-06
## 
## Residual standard error: 41.13 on 20 degrees of freedom
## Multiple R-squared:  0.7898, Adjusted R-squared:  0.7583 
## F-statistic: 25.06 on 3 and 20 DF,  p-value: 5.593e-07
## Analysis of Variance Table
## 
## Response: resistencia
##           Df Sum Sq Mean Sq F value    Pr(>F)
## tipo       3 127158   42386  25.055 5.593e-07
## Residuals 20  33834    1692