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Probability density functions

  1. Jul 16, 2010 #1
    This could go in the homework section I suppose, but I couldn't follow the guidelines, so I'll try asking it here.

    The attached image is a probability distribution for measured fibre angles from a spray up carbon fibre process. This is in a report that I need to explain. To get the probability distributions on the Y axis, would one just add up all the fibres, and divide that total by the number between a given orientation?

    Attached Files:

  2. jcsd
  3. Jul 16, 2010 #2


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    I'm not sure what you are asking. The data appears to follow a Gaussian Distribution (i.e. Normal Distribution). The way to interpret the graph is like this: For the 6k 115mm fibers, there is a 0.29 probability that the in-plane fiber orientation is approximately 0.0 radians.

  4. Jul 17, 2010 #3
    I'm asking how would generate the probabilities on the Y-axis?
  5. Jul 17, 2010 #4


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    Your graph shows the y-axis as "probability" already. So there's nothing to generate.

  6. Jul 18, 2010 #5
    I know it does, what I'm asking is how was it obtained in the first place? Would you just add up the number of fibres between a certain angle and then divide by the total number of fibres? And that gives probability?
  7. Jul 18, 2010 #6


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    It's generated by looking at all the fibres, putting each one into a category (of orientation), and counting up how many fibres are in each category; then expressing that number as a proportion of the total number of fibres.

    This should have been posted in homework help.
  8. Jul 18, 2010 #7
    Yes, that's what I thought, thanks for your help, maybe it can be moved?
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