conf intervals

CFA Level I Quant
#1

In calculating ranges using given confidence levels, I’m confused as to what is expected from candidates…do we need to memorize the common confidence levels? As in:

-95%=1.96 or 2

-90%=1.645 or 1.65

-68%=1

I hope I am not mis-remembering here, but I belive I’ve answered some Kaplan questions that DON’T provide a snapshot of the Z table indicating we have to memorize these common Z values (which is abolutely doable), but I also beleive I’ve come across exmaples where they give you a snapshot of the Z table to use.

What should I expect on the exam? Should I have common crititcal values memorized and if so, which ones?

Thanks!

#2

I wouldn’t worry too much about memorizing a lot of Z, Chi, T, F values. But assume that in statistics, knowing that 95%=1.96 or 90%=1.65 at 1-tailed distribution is like knowing 11^2 = 121 and 12^2 = 144 in algebra/arithmetics. I mean, they are too much used, almost always, that memorizing them is a lot of help.

#3

That’s essentiallywhat I was thinking…thanks!

#4

You do need to know the common z-table values:

  • μ ± 1_σ_ : 68%
  • μ ± 1.645_σ_ : 90%
  • μ ± 1.96_σ_ : 95%
  • μ ± 2.58_σ_ : 99%
#5

Memorizing it helps me solve a question in less time.

#6

Why do you discount me by 90%?