Question

4. Using R code, compare the pdfs of three normal random variables, one with mean 1 and standard deviation 1, one with mean 1 and standard deviation 10, and one with mean -4 and standard deviation 1.

Thank you

Answer 1

If we plot three pdf separately we get:

• Mean=1, SD=1

R code: ggdistribution(dnorm,seq(-4,4,0.1),mean=1,sd=1)

​​​​​​​​​​​​Mean=1,SD=10

R code: ggdistribution(dnorm,seq(-10,5,0.1),mean=1,sd=10)

Mean=-4,SD=1

R code: ggdistribution(dnorm,seq(-30,35,0.1),mean=-4,sd=1)

For comparison we plot them into one graph and get:

Red: mean=1 SD=10

Blue: mean=1 SD=1

Yellow: mean=-4 SD=1

R code:

p=ggdistribution(dnorm,seq(-30,35,0.1),mean=1,sd=1,colour='blue')
p=ggdistribution(dnorm,seq(-30,35,0.1),mean=1,sd=10,colour='red',p=p)
ggdistribution(dnorm,seq(-30,35,0.1),mean=-4,sd=1,colour='yellow',p=p)

​​​​​​​