Normal distribution - online advertising

hi, i have to calculate how many impressions we have to sell to our customers, if we want to guarantee them 1000 clicks at a service level of 98%.

mean and standard dev are given.

how to solve this? I'm a bit distracted by the 98%.

Last edited:


Well-Known Member
Hi Alex,

Dear Dason tries to say that you need to try to calculate and show us what you did. Z-table shows the result for the standard normal distribution.
I think z-table is prehistoric, but if you force to use it, you may look at your table and the following interpretation of the table:
Last edited: