R Script - Overlay Normal Distribution Curve

[Anonymous]

Hi everyone, 

Having a bit of an issue overlaying a normal distribution curve on a histogram visual, using R scripts. 

# The following code to create a dataframe and remove duplicated rows is always executed and acts as a preamble for your script: 

# dataset <- data.frame(Ratings)
# dataset <- unique(dataset)

# Paste or type your script code here:
library(ggplot2)
ggplot(data=dataset,aes(x=dataset$Ratings)) +
    geom_histogram(aes(y=..density..),col="#ffffff",fill="#bfd730") +
    labs(title="Employee 2019 Performance Rating", x="Performance Ratings", y="Frequency") +
    geom_density(col=2) 

#Adding Normal Curve 
ratings_norm_curve=rnorm(length(Ratings),mean(Ratings),sd(Ratings))

#Adding it to Histogram 
lines(density(ratings_norm_curve, adjust = 2), col="blue", lwd=2)

What might I be doing wrong here?  

[Icey · Accepted solution]

Hi @Anonymous ,

Sorry to reply late. Please check whether this could meet your requirements:

library(ggplot2)
ggplot(data=dataset,aes(x=dataset$Ratings)) +
    geom_histogram(aes(y=..density..),col="#ffffff",fill="#bfd730") +
    labs(title="Employee 2019 Performance Rating", x="Performance Ratings", y="Frequency") +
    geom_density(col=2) +
    stat_function(fun = dnorm, 
        args = list(mean = mean(dataset$Ratings, na.rm = TRUE), 
                    sd = sd(dataset$Ratings, na.rm = TRUE)), 
                    colour = 'blue') 

Best Regards,

Icey

If this post helps, then please consider Accept it as the solution to help the other members find it more quickly.

[German_Cruz]

Why the frequency shown in decimals (x axis)? 

[Anonymous]

@Icey  is it possible to show the count of frequency on the x-axis of this code?

[Anonymous]

Yes thank you so much!!! 🙂 

[Icey]

Hi @Anonymous ,

Please share me some dummy sample data, not real data, for test.

Best Regards,

Icey

If this post helps, then please consider Accept it as the solution to help the other members find it more quickly.

[Anonymous]

@Icey  apologies for the delay, but you I curated the dataset for you - it's a sample, and within the spreadsheet I've included the current visual output, the code I'm using, and a desired outcome statement. 🙂 

Let me know what you've come up with! Appreciate your assistance with this. 

Thanks Much!