# statistics

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**looking for someone to varify my work please**
.

Question:

A standard placement test has a mean of 105 and a standard deviation of ó = 13. Determine the minimum sample size if we want to be 99% certain that we are within 3 points of the true mean.

Answer:

N = ( zc ó/E)^2

= (2.575 x 13/3)^2

= 121