Normalize values to group means — normalize_group

This function computes the mean of each group, then divides each observation by its corresponding group mean. This is commonly done when pooling data across environments.

normalize_group_mean(x, group)

Arguments

x: the variable containing the data to normalized
group: the variable containing the groups

Value

Returns a vector of normalized values

Details

Computes the mean for each group, then divides each value by the mean for the corresponding group.

References

“Composite Materials Handbook, Volume 1. Polymer Matrix Composites Guideline for Characterization of Structural Materials,” SAE International, CMH-17-1G, Mar. 2012.

Examples

library(dplyr)
carbon.fabric.2 %>%
filter(test == "WT") %>%
  select(condition, strength) %>%
  mutate(condition_norm = normalize_group_mean(strength, condition)) %>%
  head(10)
#>    condition strength condition_norm
#> 1        CTD  142.817      1.0542187
#> 2        CTD  135.901      1.0031675
#> 3        CTD  132.511      0.9781438
#> 4        CTD  135.586      1.0008423
#> 5        CTD  125.145      0.9237709
#> 6        CTD  135.203      0.9980151
#> 7        CTD  128.547      0.9488832
#> 8        CTD  127.709      0.9426974
#> 9        CTD  127.074      0.9380101
#> 10       CTD  126.879      0.9365706

##    condition strength condition_norm
## 1        CTD  142.817      1.0542187
## 2        CTD  135.901      1.0031675
## 3        CTD  132.511      0.9781438
## 4        CTD  135.586      1.0008423
## 5        CTD  125.145      0.9237709
## 6        CTD  135.203      0.9980151
## 7        CTD  128.547      0.9488832
## 8        CTD  127.709      0.9426974
## 9        CTD  127.074      0.9380101
## 10       CTD  126.879      0.9365706