Trouble with aggregating/grouping data on bar chart

[BenRichardson]

I am trying to create a simple bar chart, where it will show the amount of minutes students have spent in a particular room, with those minutes broken down by the grade they are in.  However, when I put the total minutes on the y-axis and the grade on the x-axis, it is telling me that each grade is spending 100% of the grand total of minutes in the room.  Obviously, this is not possible, it should be more like kindergarten is spending 25% of the total time in the room, 1st grade 25%, etc.  Each student is only assigned 1 grade (0-4).  A picture of my chart is posted below where I am getting the error.

[BenRichardson · Accepted solution]

I figured it out- just needed to change the cardinalities

[BenRichardson]

I added a calculated field to visit log to get the total minutes for each visit using this formula in the data view:

Time Spent (Minutes) = DATEDIFF ( 'Visit Log'[Enter Time], 'Visit Log'[Exit Time], MINUTE )

I then selected the data type as "Whole Number"

[BenRichardson]

Here are samples of my tables

Visit Log:

Timestamp	What is the Student ID?	Before Room: How was the student feeling?	After Room: How was the student feeling?	What time did the student enter the room?	What time did the student leave the room?	(Optional) Enter any additional notes	Who recommended the BeWell visit?
	91	Overwhelmed	Silly	9:17:00 AM	10:05:00 AM	Notes	Student
	92	Nervous	Excited	9:19:00 AM	10:08:00 AM	Notes	Student
	93	Bored	Bored	9:21:00 AM	10:11:00 AM	Notes	Student

Student log:

Timestamp	Student ID	Enter the student's first name	Enter the student's last name	Enter the student's date of birth	Enter the student's gender	Enter the student's race	Enter the student's grade
	91	JAMES	Smith	8/4/2011	Male	Asian or Pacific Islander	1
	92	JOHN	Johnson	9/4/2011	Male	Black or African American	1
	93	ROBERT	Williams	10/4/2011	Male	Hispanic or Latino	2

[BenRichardson]

Here is my relationship - each student ID has one record for visit log and one for student log