# Pearsons rank bivariate correlation Help!

• Jun 14th 2013, 02:24 PM
squidders
Pearsons rank bivariate correlation Help!
Helloooo

I am assessing the correlation between two variables;

For pearsons rank you need both variables to be of normal distribution and be continous data?

1 of my variables are median dates between two time points, there are 140 pieces of data and they are not at regular intervals.

The other variable is continous and normally distributed.

Can I use pearsons?

Thanks (Happy)

Ali
• Jun 15th 2013, 12:12 AM
chiro
Re: Pearsons rank bivariate correlation Help!
Hey squidders.

How big is your data sample? If you have enough samples then expectations (i.e. means) will have an approximate normal distribution.
• Jun 15th 2013, 03:28 AM
squidders
Re: Pearsons rank bivariate correlation Help!
The sample size is 161.

Even if the data is normally distributed, I thought date was discrete data not continous?

Can I use pearsons as it is a large sample size?

Thanks Chiro!
• Jun 15th 2013, 05:05 PM
chiro
Re: Pearsons rank bivariate correlation Help!
If you have enough points in the distribution, you may be able to assume continuity in the distribution.

Given you sample size I think you might be able to use the normal correlation co-efficient.

I'm basing this on the CLT where the distribution of the mean (of some arbitrary distribution) approaches a Normal distribution regardless of the input distribution.