Anscombe dataset

References

Load packages

library(dplyr)
library(ggplot2)

Create dataset

dat <- datasets::anscombe
datLong <- data.frame(
    group  = rep(1:4, each = 11),
    x = unlist(dat[,c(1:4)]),
    y = unlist(dat[,c(5:8)])
    )
rownames(datLong) <- NULL
datLong

##    group  x     y
## 1      1 10  8.04
## 2      1  8  6.95
## 3      1 13  7.58
## 4      1  9  8.81
## 5      1 11  8.33
## 6      1 14  9.96
## 7      1  6  7.24
## 8      1  4  4.26
## 9      1 12 10.84
## 10     1  7  4.82
## 11     1  5  5.68
## 12     2 10  9.14
## 13     2  8  8.14
## 14     2 13  8.74
## 15     2  9  8.77
## 16     2 11  9.26
## 17     2 14  8.10
## 18     2  6  6.13
## 19     2  4  3.10
## 20     2 12  9.13
## 21     2  7  7.26
## 22     2  5  4.74
## 23     3 10  7.46
## 24     3  8  6.77
## 25     3 13 12.74
## 26     3  9  7.11
## 27     3 11  7.81
## 28     3 14  8.84
## 29     3  6  6.08
## 30     3  4  5.39
## 31     3 12  8.15
## 32     3  7  6.42
## 33     3  5  5.73
## 34     4  8  6.58
## 35     4  8  5.76
## 36     4  8  7.71
## 37     4  8  8.84
## 38     4  8  8.47
## 39     4  8  7.04
## 40     4  8  5.25
## 41     4 19 12.50
## 42     4  8  5.56
## 43     4  8  7.91
## 44     4  8  6.89

Linear regression for each

datLong %.%
    group_by(group) %.%
    do(function(DF) {
        resLm <- lm(y ~ x, data = DF)
        coef(summary(resLm))
    })

## [[1]]
##             Estimate Std. Error t value Pr(>|t|)
## (Intercept)   3.0001     1.1247   2.667  0.02573
## x             0.5001     0.1179   4.241  0.00217
## 
## [[2]]
##             Estimate Std. Error t value Pr(>|t|)
## (Intercept)    3.001      1.125   2.667 0.025759
## x              0.500      0.118   4.239 0.002179
## 
## [[3]]
##             Estimate Std. Error t value Pr(>|t|)
## (Intercept)   3.0025     1.1245   2.670 0.025619
## x             0.4997     0.1179   4.239 0.002176
## 
## [[4]]
##             Estimate Std. Error t value Pr(>|t|)
## (Intercept)   3.0017     1.1239   2.671 0.025590
## x             0.4999     0.1178   4.243 0.002165

4 graphs

ggplot(data = datLong,
       mapping = aes(x = x, y = y, group = group)) +
    layer(geom = "point") +
    layer(geom = "smooth", method = "lm", fullrange = TRUE) + 
    facet_wrap( ~ group) +
    theme_bw() +
    theme(legend.key = element_blank())

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