The same as Q1: Assume the printer cartridges in average can print 12,000 pages with 800 pages as its standard deviation (= 12000, = 800), and it is a bell-shaped distribution for the number of pages (X) it can print before running of of ink.(X is a random variable, isn't it?)

Using Normal distribution table to answer (4 decimals)

What is the chance that your cartridger can print less than 12,800 11,945 pages? That means in Math: Prob(X < 11,945) or in short: P(X < 11,945) = ?

Tip: You can use the same tip in Q1 to calculate how many standard deviation away from the mean: Then, use Case 1 in the Excel to get the answer.