 # BA II short cut question

Can someone educate me how to add my numbers fast on BA II calculator. For example, when I am working on standard deviation problem for numbers 1, 2, 3, 4,5. Mean is 3 so standard deviation(Population) = sqrt of [(1-3)^2 + (2-3)^2 +(3-3)^2 + (4-3)^2 +(5-3)^2] / 5. This kind of problem I store fist calculated value in mem1 and second mem2 all the way to mem5 and eventually recall one after one to add up. Is there any better way I can add up the numbers as I am calculating the each square. Thanks in Advance.

This has been posted several times in the last couple of days: Here’s how you enter info on the TI BAII, click 2nd then DATA (over the 7). Then click 2nd and CE/C (CLR WORK). Now, X01 shows up, enter your first data point (return for yr. 1 for example). Hit enter and then the down arrow twice. Now, X02 shows up, enter your second data point (return for yr. 2). Do that until you have completed all the years. Now, hit 2nd then STAT (over the 8). Then use the down arrow to scroll through the results… To get correlation, you have to input data in Y01, Y02, etc., as well. When you hit 2nd then STAT, hit the down arrow 10 times to “r”…

st dev of a population? is that square root of sum of squared deviatons (X1 - mean) divided by N if sample, it is N - 1 in denom

do 2nd . this will bring up a data menu. you enter 1 as your X01 hit [enter][arrow down][enter][arrow down]. Now you are at X02, enter your next value and so on. At X05, just hit enter. then do 2nd  this brings up a stat menu. You can just hit the down arrow to scroll through the different stat formulas, the first one is n, then x-bar, the sample std. dev, then pop. dev. and all of them are calculated for you. nice and quick. You can also calculate covariances and correlations if you enter in Y values in the data menu.

Lloyd Wrote: ------------------------------------------------------- > do 2nd . this will bring up a data menu. you > enter 1 as your X01 hit . Now you are at X02, > enter your next value and so on. At X05, just hit > enter. then do 2nd  this brings up a stat menu. > You can just hit the down arrow to scroll through > the different stat formulas, the first one is n, > then x-bar, the sample std. dev, then pop. dev. > and all of them are calculated for you. nice and > quick. You can also calculate covariances and > correlations if you enter in Y values in the data > menu. I’m assuming you’re talking about calculating covariance by hand, since the DATA/STAT functions gives you sigmaX, sigmaY, and correlation???

yep, I forgot it wasn’t on the stat menu. but the formula is easy enough

Wow, Thanks for quick answers. Appreciate it.