Tag: percentages

Vegetable shopping – It’s not about percentages

Some habits are hard to change. One that is especially hard to change is bargaining for vegetables. I was trained well, I must say, in the bazaars of Jayanagar 4th Block Shopping Complex. I was taught that one needs to do a full round of the market before making any purchase, in order to understand the “market price”. I was taught  techniques that would make the shopkeepers give the goods for the price I offered, I was told what demographics to approach for what kind of vegetables, and over time I must say I became an excellent vegetable shopper, when sent to Jayanagar 4th Block that is.

Another thing that is hard to change is willingness to pay, and this is where I see some irrationality. For example, I’ve just returned from the fruit and vegetable shop close to my house, having refused to buy a cucumber because the shopkeeper asked for Rs. 10 for it, a 100% markup on the not-so-longterm average price of Rs. 5. And that is precisely the problem – looking at it as percentages.

We don’t usually consume too much cucumber. If I’d bought that cucumber it would’ve lasted about a week. So by refusing to pay the “100% premium” for it, I’ve essentially saved my family a maximum of five rupees over the course of a week (and this is in the best case – conditional on my being able to procure cucumber at the “normal rate” soon. Else the loss is larger). And given our not-so-inconsiderable weekly expenses, and the fact that our “discretionary spend” is an order of magnitude larger than the five rupees I’ve saved on the cucumber, this just doesn’t make sense.

The mistake we make here is to look at the percentage increase in weekly budget of the particular item, and base our decision on that. Instead, if we were to look at the increase in the “total weekly budget” (across all items), that could help us get a more realistic figure for our willingness to pay for certain things.

Of course, the big problem here is that even if my rational mind says this, there’s a behavioural issue in paying much more than the price we’ve been “anchored” to. I don’t know how we need to get over this.

Gyaan From a Former All India Topper

CAT is less than a month away. Or more, depending on when you’re writing it. If any aspirants are reading this, I have just one piece of advice for you – which no one in any CAT Factory will give you. It’s about going for it. About batting like Sehwag. About reaching out far outside the off stump and playing every ball. I just want to assure you that percentages are in favour of this kind of a game.

In my zamaana, every correct answer in CAT gave you one mark, and every incorrect answer took away a third of a mark. Every question had four possible answers of which exactly one was correct. This negative marking had a completely psyching out effect on most takers, and people are afraid to go for it. And six years back, I liked it. For it made my own risk-taking strategy much easier – since I could now afford a larger number of errors.

The arithmetic is simple. Even if you have no clue about the question, and just put inky-pinky-ponky (or even better mark ‘C’, since years of research has proven that it’s the statistically most probable answer in CAT) you have one-fourth chance of getting it right – which gives a three-fourth probability of getting it wrong. And given the payoffs for correct and incorrect answers (1; -1/3) you can clearly see that the expected payoff of taking a completely random guess is ZERO!

So while this obviously rules out insane inky-pinky-ponkying, what it does tell you is that if you can eliminate at least one of the four choices, you are in the money! If you have to pick one of three possible answers, the expected payoff is 1/9 which is greater than zero. Yeah it doesn’t look very high but then the expected payoff is positive! So you need to go for it.

Back when I was in my 3rd year, there was some free mock CAT at IITM. And some of us 3rd years went just for the heck of it. I attemped 130 out of 150 questions, getting 90 right and 40 wrong. It still gave me a significantly higher score than any of my seniors (who were writing CAT that year) – most of whom attemped not more than seventy. Later that day a senior called me aside and told me that the art of CAT was about leaving questions. And that it was all about the questions that you left.

Leaving the ball makes sense in cricket where one mistake ends your innings. What if instead of ending your innings you were just deducted 2 runs everytime you got out? Would you still leave the balls outside off and play the waiting game? How on earth would you score runs if you were to leave every ball? It’s all about scoring, and you can score only if you attempt a shot.

I understand that CAT format has changed now and you have 5 possible correct answers for every question while the negatives are still at 1/3. Even then, if you can eliminate two out of the five answers (shouldn’t be too gouth), you have a positive payoff. And you must go for it. Keep in mind that you can’t score if you don’t play the ball.

I leave you with a video. The message is in the name of the song. Idu One Day Matchu Kano. This is a one day match dude. So you must go for every ball. And look to score.