# Kyla's Test

• November 16th 2008, 09:43 PM
magentarita
Kyla's Test
The probability that Kyla will score above a 90 on a mathematics test is . What is the probability that she will score above a 90 on three of the four tests this quarter?
• November 16th 2008, 10:46 PM
mr fantastic
Quote:

Originally Posted by magentarita
The probability that Kyla will score above a 90 on a mathematics test is p . What is the probability that she will score above a 90 on three of the four tests this quarter?

A necessary piece of information is missing. The red p marks the spot.

The answer will be ${4 \choose 3} p^3 (1 - p) = 4 p^3 (1 - p)$ where p is the value you haven't given.
• November 17th 2008, 10:15 PM
magentarita
ok............
Quote:

Originally Posted by mr fantastic
A necessary piece of information is missing. The red p marks the spot.

The answer will be ${4 \choose 3} p^3 (1 - p) = 4 p^3 (1 - p)$ where p is the value you haven't given.

Thank you very much.