The first step in data science and machine learning is always defining the problem that you want to 1
solve and making sure that you're asking the right questions. 2
So in this video let's specify the exact question that we want to answer. 3
We're going to formulate our goal and we're going to set the context for the upcoming videos. 4
Imagine that you're living in the beautiful city of Boston, Massachusetts in the United States. 5
You moved there a number of years ago and you're doing your best to pick up the local accent. 6
Now I am told that you can't really do a Boston accent without liberal use of profanity so I will resist 7
the temptation of doing an impression of one right now. Anyhow, 8
imagine you're living in Boston and you're working in the real estate business and you have this friend 9
who recently moved to the city, 10
so you decide to meet up with them in one of the local coffee shops. You two get talking and he asks 11
you 12
"So uh I'm looking to buy a place to live here, 13
how much does a house cost in Boston?". Now this is the opportunity that you've been waiting for all your 14
life. 15
So you grab your little calculator and your little model house from your bag and you put it onto the 16
table and coyly respond: 17
"Well it depends what kind of house are we talking about." 18
"I don't know", 19
says your friend. 20
How much does a house cost around here? 21
You work in real estate, 22
you should know. Your friend has completely ignored your request for more information and to be more 23
specific and continues to press you on an answer. 24
So you respond: 25
"It depends on the size of the house, mate. 26
What are we talking about? 27
A shoebox of an apartment or an MTV Cribs style mansion? Also, 28
which part of town do you want to buy a house in - downtown or in the suburbs?" 29
Your friend just stares you down and says "Just give me a number". What are you gonna say to that? With 30
no information about the kind of house, 31
no information about the home's features, 32
no information on the location, 33
what's the best possible answer that you can give your friend? 34
What's the most truthful way to answer this question? 35
The answer is just the average home price in Boston, right? 36
So you turn to your friend smile and say "567500 dollars", 37
and you silently decide that you never want to meet somebody who is so poor at phrasing their questions 38
ever again. 39
The next morning you roll into your snazzy downtown office and your boss calls you over and says "I've 40
got a new project for you. 41
Our real estate agents need a software tool that helps them value homes in the Boston area 42
at the push of a button. This tool needs to output a benchmark price based on the characteristics of 43
the home. And by characteristics, 44
I mean things like how many rooms the home has or how much crime there is in the area plus a whole bunch 45
of other factors. Also, 46
we want to see the contribution of each factor in your model so don't create a magic black box that 47
just spits out a number. 48
Our agents each know which features of a house are more important in determining the house price and 49
which factors are less important in determining the house price. 50
Our real estate agents need to know what the premium is for living in a home where parents can send 51
their kids to a good school. 52
In other words this valuation tool needs to be tractable. 53
Also if your tool doesn't completely suck, then we might even put it up on our website for anyone to 54
get a valuation for their home. 55
The same way that companies like Zillow do it or Zoopla in the UK. Can you do this? 56
Do you accept this mission?" 57
So you look at your boss and you think yourself 58
"You know what, this sounds like the kind of thing that my friend from the coffee shop would have needed. 59
And also this sounds like an awesome project." 60
So you look your boss square in the eyes and say "Roger that, I can do this" and you fist bump your boss 61
because that's what people do in Boston and in stock photography. 62
Also the intern standing next to you joins in with the fist bump and off you go.