CODEWITHSUNDEEP
rstatisticsmeandifference
Marco Pastor Mayo
Marco Pastor Mayo

Reputation: 853

Calculate the mean difference within and between groups

I have two sets of values as follows:

x <- as.vector(c(1, 2, 3, 2, 1))
y <- as.vector(c(7, 7, 8, 9, 9))

I am trying to calculate the mean difference of the values in each group and also the mean difference of the values between groups.

In this small example, the mean differences would be, for x, (1+2+1+0+1+0+1+1+2+1)/10=10/10=1

And for y it would be (0+1+2+2+1+2+2+1+1+0)/10=12/10=1.2

Between the groups, it would be (6+6+7+8+8+5+5+6+7+7+4+4+5+6+6+5+5+6+7+7+6+6+7+8+8)/25=155/25=6.2

I am hoping that there is some way to do this with code that is simpler.

Upvotes: 1

Views: 95

Answers (1)

tmfmnk
tmfmnk

Reputation: 39858

One possibility could be:

xy_diff <- abs(sapply(x, "-", y))
sum(xy_diff)/(dim(xy_diff)[1]*dim(xy_diff)[2])

[1] 6.2

x_diff <- abs(sapply(x, "-", x))
x_diff <- x_diff[upper.tri(x_diff)]
sum(x_diff/length(x_diff))

[1] 1

y_diff <- abs(sapply(y, "-", y))
y_diff <- y_diff[upper.tri(y_diff)]
sum(y_diff/length(y_diff))

[1] 1.2

Upvotes: 1

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