Latitude and Longitude Coordinates in Wrong Hemisphere

[MorganCunningham]

This is my first time using ArcMap (10.1) for a project and I'm having some trouble! I am trying to plot points off the coast of the Northeast Atlantic Coast, and they are ending up off the coast of Ghana. I've tried importing from a csv file and an excel spreadsheet. I attached a sample of my data. 

I know the western hemisphere longitude values must be negative and northern latitude values must be positive. Any other reason why I am not plotting these points correctly?

[NeilAyres]

Are you correctly defining which is X and Y.

Longitude = X; Latitude = Y

[MorganCunningham]

Yes I am, when I plotted the exported data I put the longitude as X and latitude as Y.

[GabrielUpchurch1]

Are you specifying a coordinate system?  You should probably be using GCS_WGS_1984.  I tested with your data and it worked correctly.  If you are not sure what I mean, just ask.

[MorganCunningham]

Okay! How do you specify a coordinate system? Do you specify when you plot the data?

[GabrielUpchurch1]

What procedure are you using to plot the data?  Here is what I did:

1. Add spreadsheet to ArcMap.

2. Right-click on spreadsheet name and select "Display XY Data."

3. "Edit" coordinate system section and select GCS_WGS_1984.

[MorganCunningham]

Figured out how to edit the coordinate system...thank you so much! I figured it had to be something pretty simple

[SimonKettle]

This might be useful for future iterations of this problem: https://community.esri.com/groups/coordinate-reference-systems/blog/2018/12/12/checklist-adding-coor...