Question 742439
A department store, on average, has daily sales of $29,539.06. The standard deviation of sales is $2,000. On Tuesday, the store sold $34,574.94 worth of goods. Find Tuesday's z score. Was Tuesday an unusually good day?
<pre>
{{{z}}}{{{""=""}}}{{{(x-mu)/sigma}}}{{{""=""}}}{{{(34574.94-29539.06)/(2000)}}} = 2.52

That means that Tuesday's sales were 2.52 standard deviations above the
mean and by the empirical rule 95% of the sales are no more than 2
standard deviations above the mean, so indeed Tuesday's sales were
unually good.

Edwin</pre>