# Thread: I do not understand standard normal distribution

1. ## I do not understand standard normal distribution

Hi guys, I'm in dire help for standard normal random variable.
I've looked at examples but they don't seem to help with the following questions.

P ( z <= 1)

P ( z <= 2)=

P (Z < 2) =

P ( Z = 0 ) =

P( z <= 1.34) =

Now I'm using r and am thinking its
pnorm(z =<) but can't get it to compute

2. ## Re: I do not understand standard normal distribution

Do you understand how to solve them using the z-table? This would be a good start. I'm unfamiliar with R. Maybe someone else can help you to that end. http://www.normaltable.com

3. ## Re: I do not understand standard normal distribution

P ( z <= 1)

P ( z <= 2)=

Code:
``````?pnorm

# P(Z<= 1 ) = 0.8413447
pnorm(1, mean = 0, sd = 1)
# [1] 0.8413447

# P(Z<= 2 ) =
pnorm(2, mean = 0, sd = 1)
# [1] 0.9772499``````
So what is:

P( z <= 1.34) =

It says: what is the probability of ONE (so n=1) random standard (so mean=0 and standard deviation =1) normal variable being less or equal to 1.34?

And please don't double post. It is annoying.

4. ## Re: I do not understand standard normal distribution

Originally Posted by GretaGarbo
P ( z <= 1)

P ( z <= 2)=

Code:
``````?pnorm

# P(Z<= 1 ) = 0.8413447
pnorm(1, mean = 0, sd = 1)
# [1] 0.8413447

# P(Z<= 2 ) =
pnorm(2, mean = 0, sd = 1)
# [1] 0.9772499``````
So what is:

P( z <= 1.34) =

It says: what is the probability of ONE (so n=1) random standard (so mean=0 and standard deviation =1) normal variable being less or equal to 1.34?

And please don't double post. It is annoying.

Hi there,
so to calculate 1.34 is more or equal to z, we would just replace the formula with 1.34 so..
pnorm(1.34,mean=0,sd=10)?

To calculate Z < 2 we would just use pnorm(2...?

Thank you very much for your response
Yes I am sorry about double posting, not sure if this is the right subtopic to post on.

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