# mean and variance

7) suppose the average weight of an item labeled 16 ounces actually has mean 17 ounces and variance 4 (ounce^2). What is the approximate probability that the combined weight of 25 items exceeds 445 ounces? What theorem is useful in answering this question?

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#### Solution Preview

This is a standard normal distribution theorem question

E(X)=17 and Var(X)=4

Then 25X is also a normal ...

#### Solution Summary

This shows how to find the probability that a weight is in a certain range given mean and variance.

$2.49