First case study: There are two options to send advertizing mails- first class (costs 50 cents) and third class (costs 40 cents). What class should be chosen to send mail offers for credit cards. At this point- you should ask the difference between the two mails- So, they will say- First class has a delivery rate of 100% but Third has 90%. So, which option is better now? The correct answer is- it depends. If money is a constraint or the # of people we can send mails to is a constraint. So, take money constraint as $1000 and do the calculation- Third will come better. Then take 100 people as constraint, then First will come better. Then at what point are both the same? (They will ask this). Try to make two graphical lines for the two options (X axis as # os people. Y axis as money). For the two options discussed below, plot the points, and then find where the lines are intersecting). For second case study- it was about call center activity. For Sunday to Saturday, they gave the data for # of calls, average call talk time and the average hold time. So, they asked what's the average talk time for the week? The trick is to calculate the weighted average talk time. So multiply the average talk time for each day by the # of calls, add them all and divide by the total sum of # of calls for the week. What's the advantage fo weighted average? This way, the outliers can not affect the results too much if their total contribution is very little. Then they said- if on an average it takes 100 seconds to handle a simple call query but 172 sec for a complex query (the call gets transferred from simple handlers to complex handlers), then what's the call trasfer rate? For this: total time for complex query is 172+100= 272. For simple= 100. So, we need to find the number of calls that get transferred from simple to complex operator. let X% be the call trasnferred and thus take 272 sec. so: avg talk time (which we found in the first part above)= 272*X + 100(1-X). My answer there came to be around 29.6%..or something. They also asked me how would I try to lower the transfer rate? I said- by automating some part and training the simple handlers to take on the complex tasks. Behavioural: if there was any conflict in a project with someone and how you solved it? Did you mentor anyone?