Discussion about math, puzzles, games and fun.   Useful symbols: ÷ × ½ √ ∞ ≠ ≤ ≥ ≈ ⇒ ± ∈ Δ θ ∴ ∑ ∫ • π ƒ -¹ ² ³ °

You are not logged in.

• Index
•  » Help Me !
•  » What is the formula for finding Z in this case?

|
Options

genericname
2012-12-03 12:58:03

Oh! I see. As always, thanks!

bob bundy
2012-12-03 10:29:30

Arrrhhh!  That's more like it.  See picture of normal distribution graph.

And further down that page you'll find that 1.96 gives the right probability.

Values for the table cannot be easily calculated which is why people use the table.

Bob

genericname
2012-12-03 09:41:20

Ah, the answers were mixed up. The answer is actually 1.96. How did they get that?

bob bundy
2012-12-03 09:21:42

hi genericname,

I'm assuming this is a normal distribution problem.

I cannot make those figures (P = 0.025 and Z = 0.7)  go together.  Is there more to this problem or have I got the wrong model?

Have a look at the interactive normal curve / table at

http://www.mathsisfun.com/data/standard … table.html

Bob

genericname
2012-12-03 06:50:36

Hi, the problem is:
Find Z.025; that is find Z which cuts off a right-hand tail probability 0.025

The "Z.025" part looks like this:
http://i.imgur.com/CnZdc.png  (didn't know how to type it out)

The answer is .70, but I don't know how it was calculated.