I was confused by question 19 in the CMP when asked to find various probabilities under a Normal distribution. The solutions assume that the standard deviation is 40 but the question reads that the variance is 40. Is this an error in the course notes?
Thanks - still think it may be an error though... Thanks for this Little Miss. I agree that that S~N(mu=200, sigma=40) is an acceptable description of a distribution. However, once the distribution is quoted without these parameter names, the second parameter should represent the variance. The Tables give the Gaussian distribution as N(mu, sigma-squared). Could any any ActEd tutors shed some light on whether this is an error? I assume the questions in the CA3 exam will be more wordy than numerical and so may give a description of the distribution. However, it could be that any distribution is written in the form above in the notes for the question so it would be useful to clear this matter up.
Earlier in the notes, the definition is given (as standard deviation), so this has been used throughout this section. But in the exam, as long as you define what you're doing, you'll be fine. You're right, I'd hope that any exam question would be perfectly clear about what they were using.
