1. Describe situations in which we use algorithms in data science
1. Describe the process for creating an algorithm
1. Create some algorithms of your own
## Define what an algorithm is
An algorithm is just a series of steps to be taken. It's what computers use to solve a problem
## Describe situations in which we use algorithms in data science
1. Grab information from the internet and present results
- What's happening in social media?
1. Given a set of data files, produce charts
- Provide analysis of a company's performance
1. Help a website provide meaningful data to users
- What posts are "trending"?
1. Machine Learning
- purpose
- representation
- extract data from data
- generalization
- make predictions from data
- forms
- supervised
- Usually requires data verified by humans
- Using existing data
- extract meaning from it
- make predictions with it
- Example 1
- Feed a computer scans of brains with cancer
- Have The computer make predictions about whether or not new images of brains show cancer
- Example 2
- Given actions of a driver, teach a computer how to drive
- Example 3
- Suppose you want to predict whether someone will make make a purchase the week after they visit your site.
- You have a set of data on previous customers, including age, interests, previous purchases, time of visit, etc.
- You know whether previous customers made a purchase within a week of their last visit.
- So, the problem is combining all the existing data into a model that can predict whether a new person will make purchase within a week.
- You can then take action and send a reminder or offer a discount.
- Amazon, Netflix, and others do this based on the history of their existing customers.
- unsupervised
- the computer will look at data and create relationships itself so it can
- extract meaning from it
- make predictions with it
- Example
- Suppose you want to understand your customer base so that you can produce appropriate segments that you can target with your next marketing campaign.
- You have a set of data about your customers, including age, location, previous purchases, time of visit, etc.
- But what characteristics should you use?
- Based on these attributes the program will find similarities and differences that provide groupings (segments) of customers.
- it will figure out people like
- the hedge fund manager's playboy son
- the single mother
- the angsty tween
- You can then take action and make an offer or recommend a product specifically to these segments.
## Describe the process for creating an algorithm
### The process
To create an algorithm for a computer program, there are a few steps to follow:
1. Think about the larger solution as a whole, but as a series of steps that you would write out for a petulant child to follow
@ -66,3 +117,11 @@ Is it peeled? - conditional coming up
The orange is now peeled - comment
You're done! Eat it! - function
```
## Create some algorithms of your own
Do the following in groups:
1. Write pseudo to to make a peanut butter and jelly sandwich
1. Given a bunch of votes on a post, create a "Recently Popular" algorithm
