Statistics + Probability

Question 1

How do you calculate the coefficient of variation

Answer 1

= standard deviation / mean

Question 2

What’s the different between frequency histogram and relative frequency histogram

Answer 2

frequency histogram has stated frequency on the y axis
whereas relative has the ‘relative’ frequency (percentages 0 to 1) on the y axis

Question 3

Calculate the standard deviation using the Bessel correction

Answer 3

Same as normal just divide by n-1 instead of n
Or
times standard deviation by (n/n-1)^1/2

Question 4

Calculate the standard deviation using the range method

Answer 4

= range / sqrt of the mean

Question 5

Based on central limit theorem calculate the mean, sd and error

Answer 5

mean done as usual
sd use range method
-+ error = sd / sqrt (n)

Question 6

Work out the P(X = 2) when the mean (x̄) is 1

Answer 6

Poisson distribution
P = (x̄^n * e^-x̄) / n!

Question 7

Work out the P(X > 2) when the mean (x̄) is 1

Answer 7

P = e^-x̄ ( x̄^n/n! + x̄^n+1/n+1! )