Hi Sorry this might be a silly question but the only part of question 4 ii) that I didn't follow was where they calculated the standard deviation. Could anybody help me with that? Thanks Tharandeep
Formula for sample standard deviation is \(\sqrt{\frac{\sum X_i^2-(\sum X_i)^2/n}{n-1}}\)=\(\sqrt{\frac{n*\sum X_i^2-(\sum X_i)^2}{n*(n-1)}}\) now you just need to get values from 5 burning costs and put values. \(\sum X_i^2=23906104\), \(\sum X_i=10900\) and n=5
Ahh right, thanks Hemant Rupani! I didn't see why we'd need to use the n on the numerator, and the n*(n-1) on the denominator, when we could use the usual sample standard deviation formula. Thanks for getting back to me so quickly.
