Hey guys I need help with this VCAA question form 2015 exam 2.
The answer says the modal inerval is 70-75, but shouldnt it be 70-74 becaues its a histogram, and like 75+ are part of the following intervals?
Thanks
You would say 70-75, because if this interval was 70-74 and the next was 75-80, then all of the values between 74 and 75 (e.g. 74.5) would be excluded. It would really be 74.9999999999999999999 going on forever but you would just say 75.
what would you do for this
If a question asks for whether a residual plot is linear or non-linear, you have to look at whether the data is randomly skattered or not.
(Images are from
here)
I would say that this plot would say that the residuals would be non-linear, as it doesn't appear to be randomly scattered, and there is a patch around the centre that has no data (or little) above the x axis, but a lot below the axis.
To linearise this, you need to apply a transformation to the data. To do this, you need to go back to the original graph and look at the shape of the data. Your teacher might have given you a diagram about what transformation to use when the graph looks a certain way. If not, you could try looking it up.
This question is 2 marks, so I would say that it would be non-linear, and therefore requiring a transformation as the question asks.