# Experienced data analyst Interview Questions

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Experienced Data Analyst interview questions shared by candidates### You have 8 marbles and a balance scale. One marble weighs more than the others, but you don’t know which one. How can you identify the heavier marble using only two weighs of the balance scale?

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We put 3 marbles on each side of the scale for a total of 6 marbles that are being weighed. We leave 2 marbles off the scale. Then, we compare the 6 marbles… There are two possible outcomes: If one side is heavier than the other then we only have 3 marbles left. Then, in the second weighing, we can compare 2 of those 3 marbles to each other. If they are the same weight, then the 3rd is the heaviest. If one is heavier than the other, then we’ve succeeded in just two weighings. If, when comparing the 6 marbles, we find that both sides are equal, then we know that the heaviest marble has to be in the 2 marbles that are not on the scale. This means that we only have to compare on those 2 remaining marbles and we have the heaviest marble in only two weighings. Less

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I wonder how they grade you if you use the simpler but slightly less effective method of going 4x4, then 2x2, then 1x1. Less

### How would you predict the number of shoes Nike will sell next month in New York?

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Historical trends, break the question by customer group, etc.

### You're going to open up a coffee shop that produces nothing but cups of coffee. It will cost you $10,000 to set up the shop. It will then cost you $1 per cup to brew coffee, which includes operational costs for your shop. You will sell your cups of coffee for $1.50 per cup. and you can assume that every cup you brew will be sold. Ignoring the time-value of money, how many cups will you have to sell to break even?

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$10,000 / ($1.50-$1) = 20,000 cups