IAI may 2006

In Q1 of IAI may 2006, I am getting the answer for variance as 195.76 because I have used the formula (1/fi-1)(fi(xi squared) -n(mean squared )-which is given in the formula page at the end of the first chapter.Whereas in the indicative solutions, the answer is 189.56 because the division takes place only by ‘n’.
Please tell me which method is correct?

p.s- is the sigma sign

 

(n-1) in the denominator is generally used when we are trying to estimate population variance using a sample. You will study these things in later chapters.
This question asks to calculate the variance of the data. So "n" denominator would've been more appropriate.
But using "n-1" wouldn't lose you marks as long as you state your assumptions correctly.

 

thank you so much.