Hi all, Quick question. If you have read the manual, or just know how to use the HP, you can calculate Standard Deviation by keying in the number, then pressing the “sum +” function, then “g” then “S”… I’m having a problem coming up with the correct answer though if the question involves a negative number. Can anyone help me with this? For example, returns are 10%, 2%, 5%, 7%…SD = 3.36 Easy The problem is if say the returns are 17%, 12.2%, 3.9%, -8.4% = 9.63 (if you do the math) With using the HP as I stated above, I get = 11.1218 Why is this? Anyone know the correct way to input this into the HP to come up w/ the correct 9.63 answer?
9.63 is population SD and 11.12 is sample SD
Hi Choate05, the difference is because of s^2 = (1/n)*[x_1^2+x_2^2+…+x_n^2]^0.5 and s^2 = (1/n-1)*…, as spirit already said. Daniel www.berufsexamen.de
Furthermore, and take a look in the manual to confirm this, to get the population SD you can add the sample mean to the sample and then press g then s to get the population SD.
That makes sense. I figured but didn’t look up the correct way to input based off of the sample vs population SD. I have the manual, just yet to look at that part again b/c if need be I can calculate by hand! It’s amazing all the little things you need to know. I feel sorry for first time takers (don’t get too freaked out noobies :p). Although some are smarter than I, it’s taken me a considerable amount of time to really learn all the stuff, and I’m a finance major w/ a BA…lol. It was several years ago but still its painful the amount of hours you have to spend. One piece of advice I would have for new timers, is this…Just give up your life and totally, dedicate all (most all) of your free time to studying CFA L1, and you’ll pass. Until you totally do that, you may not have enough time to learn it all, as crazy as that sounds… Thanks to all who replied. -C