Pearson Correlation

[Kerrowman]

I am trying to run a Pearson correlation on some battery capacity data as shown in this table.

The code I am using is shown in the grab here (I don't seem to have much luck when inserting code directly):

I don't understand the error which seems to suggest that I am missing an argument.

The NULL hypothesis is that there is no correlation between the Predicted Capacity and the Measured Capacity and the Alternative hypothesis is that there is a relationship. Also, I am not fully sure that the "alternative' is 'Less' rather than 'Greater'.

Have I got my R code correct?

Thanks

Julian

[vedoa]

Hi @Kerrowman

@Kerrowman

The code I am using is shown in the grab here (I don't seem to have much luck when inserting code directly):

just type your code into the following format

```
put code in here
```

@Kerrowman

I don't understand the error which seems to suggest that I am missing an argument.

You have to delete the pipe %>%. So your code has to be

CapacityPb # see how i don't use the pipe operator here
cor.test( rest of your code )

what happened is that your pipe is using the CapacityPb data frame and injecting it into corr.test which lead to the error message.

[Kerrowman]

Thanks. I was under the impression that the pipe operator is normally required to use a dataset.

Is there any need to run a t-test on the data as well to further support the Pearson correlation?

[randyzwitch]

@Kerrowman

Thanks. I was under the impression that the pipe operator is normally required to use a dataset.

The pipe operator is known as "syntactic sugar" in that it's never required for use. When you are using it, it's a way of saying "this R object on the left hand side should be passed to the function on the right hand side". It's a way to avoid assigning intermediate results to a named R object, or generally a way for people to organize their code as a pipeline of operations.

In your next bit of code, you explicitly pass the data you want to use in via the CapacityPb$PredCap, CapacityPB$MeasCap... arguments. So cor.test already has all the information it needs to run; getting the extra reference to CapacityPB via the pipe operator is basically saying "What do you want me to do with that extra information?" and throws an error.

Best,
Randy