Time Line

Time Line

Hello, i am trying to create a timeline in 15 minute segments using a form, this will allow the user to input a total amount of staff for that task from their preferred start time up to the finish time.

my form has the following fields

Day Of the Week - Dropdown
Task / Duty - Single Field
06:00
06:15
06:30
06:45
07:00 - Decimal fields
etc etc

so for example i can enter the following:

Sunday
Class teacher A
06:00 - 0.00
06:15 - 0.00
06:30 - 1.00
06:45 - 1.00
07:00 - 2.00


this should then show in a report that on sunday there will be from 06:00 - 06:15 no teacher in class A, then it should show 06:30-06:45 1 teacher in class A, and then 2 from 07:00.

The problem i have is i can store each value correctly but when it comes to the reports i am unable to produce a timeline stacked bar chart to show how many teachers i have in which class at the times they are in class from.
i will need to have the report show a total Y axis of numbers of teachers and X axis the timeline for the day.
Is this possible or am i going about it the wrong way? 
i do need to show times in 15 minute increments

Thanks Chris