1. avatar says

    Hello Sir, thanks for the great work. I need a clarification. Why is it that when learning rate increases, average time also increases. I thought as learning rate increases which means people learn faster, then average time taken to produce the product should reduce. For example when first unit takes 200hrs and learning rate is 60% then average time is 120hrs for second unit, if the rate increases to 70%, the average time rather increases to 140hrs which confuses if compared to real life.

    • Profile photo of John Moffat says

      I realise that in other contexts we tend to think of it as the higher a percentage it then the better, but in the case of learning rates this is not the case.

      The lower the learning rate the faster they are learning. We would want the learning rate to be as low as possible. A learning rate of 70% is better than a learning rate of only 90% – the 70% people are learning faster.

      • avatar says

        Thanks for the quick response but still not very clear. What does the percentage really mean then? I take it as it means the rate at which the workers are learning and if so then the faster the better so the higher the rate the better. That’s why am thinking that way. Probably it means something different. I will be clear if u can help me with that thing.

      • Profile photo of John Moffat says

        Don’t look for a meaning! All it means is that the average time falls to that percentage of the previous average time.

        It is a measure for us to find how fast they are learning, but not in the way that you are trying to interpret it. Too many think that way without understanding how it is working (which is why the examiner once asked as a small part of a question – which is better, a learning rate of 80% or a leaning rate of 90%. The answer is 80%).

        (Higher percentages are not always better. If I told you that my company wastes 10% of my raw material and another company wastes 5% of its material, it certainly does not mean that my company is doing better :-) )

      • avatar says

        I got it. Thanks very much. It means For example, an 80 percent
        learning curve means the per unit average
        cumulative cost (in hours or dollars) falls to 80
        percent of the previous per unit average
        cumulative cost as the cumulative output
        doubles. Therefore the lower it falls the better.

        Thanks very much for your reply.

    • Profile photo of John Moffat says

      As is made very clear in the introduction paragraph to the Course Notes, you will not be asked for calculations on regression or on time series. (The calculations are examined in Paper F2)

      You are only expected to know the principles. I have only left the calculations in the notes (and lectures) to hopefully make the idea more clear.

    • Profile photo of John Moffat says

      Time series and regression analysis are assumed knowledge from Paper F2. The examiner has said that there will not be detailed calculations on either, but you are expected to be aware of both.
      (If you look at the course notes, it actually says this in bold letters. We update our notes every six months and everything in our notes is relevant for the December 2013 exams)

Leave a Reply