I'm using a medical insurance data set to hone my modeling skills that looks like this:
> insur_dt
age sex bmi children smoker region charges
1: 19 female 27.900 0 yes southwest 16884.924
2: 18 male 33.770 1 no southeast 1725.552
3: 28 male 33.000 3 no southeast 4449.462
4: 33 male 22.705 0 no northwest 21984.471
5: 32 male 28.880 0 no northwest 3866.855
---
1334: 50 male 30.970 3 no northwest 10600.548
1335: 18 female 31.920 0 no northeast 2205.981
1336: 18 female 36.850 0 no southeast 1629.833
1337: 21 female 25.800 0 no southwest 2007.945
1338: 61 female 29.070 0 yes northwest 29141.360
I'm using recipes
as part of the tidymodels
meta-package to prepare my data for use in a model, and I have determined that bmi
, age
, and smoker
form an interaction term.
insur_split <- initial_split(insur_dt)
insur_train <- training(insur_split)
insur_test <- testing(insur_split)
# we are going to do data processing and feature engineering with recipes
# below, we are going to predict charges using everything else(".")
insur_rec <- recipe(charges ~ age + bmi + smoker, data = insur_train) %>%
step_dummy(all_nominal()) %>%
step_zv(all_numeric()) %>%
step_normalize(all_numeric()) %>%
step_interact(~ bmi:smoker:age) %>%
prep()
Per the tidymodels guide/documentation, I have to specify the interaction as a step in the recipe
as step_interact
. However, I am getting an error when I attempt to do so:
> insur_rec <- recipe(charges ~ age + bmi + smoker, data = insur_train) %>%
+ step_dummy(all_nominal()) %>%
+ step_zv(all_numeric()) %>%
+ step_normalize(all_numeric()) %>%
+ step_interact(~ bmi:smoker:age) %>%
+ prep()
Interaction specification failed for: ~bmi:smoker:age. No interactions will be created.partial match of 'object' to 'objects'
I am new to modeling and am not quite sure why I am getting this error. I am simply trying to state that charges
is explained by all other predictors, and that smoker
(a yes/no factor), age
(numeric), and bmi
(double) all interact with each other to inform the outcome. What am I doing wrong?
From the documentation:
step_dummy(all_nominal())
turned the variablesmoker
intosmoker_yes
. Below, you'll see that I just changed the name ofsmoker
in the interaction term tosmoker_yes
.