CODEWITHSUNDEEP
rmachine-learningregression
Duba Minus
Duba Minus

Reputation: 21

How to predict future values using a multiple linear model in R?

I have a data set consisting of the Year, Credit Hours, and Number of students. I have been trying to predict future credit hours by the number of students.

df <- data.frame("year = c(2018,2019,2020,2021), "student" = c(1000,1200,1350,1450), "credit" = c(4000,4300,4730,4250))

mod <- lm(credit ~ year + student, data = df)
summary(mod)

I would like to predict the number of credit hours for the next couple of years, lets just say 2022:2025, that also factors in predicted number of students. Is there a way to do this?

year credit student
2018 4000 1000
2019 4300 1200
2020 4730 1350
2021 4250 1450
2022 NA NA
2023 NA NA
2024 NA NA
2025 NA NA

In other words, how can I use a linear model in R to predict all of these NA values? I can do this in a simple linear regression no problem, but cannot seem to get it to work in multiple form.

Upvotes: 0

Views: 307

Answers (1)

alexrai93
alexrai93

Reputation: 643

You need to pass a dataframe to predict() as the newdata argument. The data frame requires you to specify values of independent variables for each prediction. If you also want to predict the number of students based on a linear model and use that as input then you can do that step first. Something like:

lm.student <- lm(students ~ year, df)
pred.student <- predict(lm.student, newdata = data.frame(year=2022:2025))

mod <- lm(credit ~ year + student, data = df)
MyNewData <- data.frame (year=2022:2025, student=pred.student)
pred <- predict(mod, newdata = MyNewData)

Upvotes: 0

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