CODEWITHSUNDEEP
r
teresa
teresa

Reputation: 69

Create new value based on equation in R

I am new to R so I am struggling to figure out how to do this. I have a data frame with thousands of observations that looks like this

x    total  subgroup1  subgroup2
.03  1000     500       500
.04  1050     550       500
.07  1100     525       575
.08  9900     4900      5000

I am trying to come up with a weighted value for x based on the following equation.

weighted x for subgroup1 = (Σ x*subgroup1) / (Σ subgroup1)

The idea is that for each observation we multiply the x value by the subgroup 1 value and add them all together and divide it by the sum of all the subgroup values. I also want to do this for subgroup 2. I imagine I will need some type of loop function. However, I am not sure where to start in R. Any leads would be great.

Upvotes: 0

Views: 44

Answers (1)

Diego
Diego

Reputation: 356

x <- c(0.3, 0.4, 0.7, 0.8)
subgroup1 <- c(500, 550, 525, 4900)
subgroup2 <- c(500, 500, 575, 5000)
total <- subgroup1 + subgroup2
df <-data.frame(x, total, subgroup1, 
subgroup2)
x_wg_1 <- 
(sum(df$x*df$subgroup1))/sum(df$subgroup1)  
x_wg_1

Just some code using base R. No need for a loop. Just multiply vectors from the data frame and sum the elements. Then divide by then sum of another vector.

Upvotes: 1

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