Cross-Validation in Machine Learning

There is always a need to validate the stability of your machine learning model. I mean you just can’t fit the model to your training data and hope it would accurately work for the real data it has never seen before. You need some kind of assurance that your model has got most of the patterns from the data correct, and its not picking up too much on the noise, or in other words its low on bias and variance.

Validation

This process of deciding whether the numerical results quantifying hypothesized relationships between variables, are acceptable as descriptions of the data, is known as validation. Generally, an error estimation for the model is made after training, better known as evaluation of residuals. In this process, a numerical estimate of the difference in predicted and original responses is done, also called the training error. However, this only gives us an idea about how well our model does on data used to train it. Now its possible that the model is underfitting or overfitting the data. So, the problem with this evaluation technique is that it does not give an indication of how well the learner will generalize to an independent/ unseen data set. Getting this idea about our model is known as Cross Validation.

Holdout Method

Now a basic remedy for this involves removing a part of the training data and using it to get predictions from the model trained on rest of the data. The error estimation then tells how our model is doing on unseen data or the validation set. This is a simple kind of cross validation technique, also known as the holdout method. Although this method doesn’t take any overhead to compute and is better than traditional validation, it still suffers from issues of high variance. This is because it is not certain which data points will end up in the validation set and the result might be entirely different for different sets.

K-Fold Cross Validation

As there is never enough data to train your model, removing a part of it for validation poses a problem of underfitting. By reducing the training data, we risk losing important patterns/ trends in data set, which in turn increases error induced by bias. So, what we require is a method that provides ample data for training the model and also leaves ample data for validation. K Fold cross validation does exactly that.

In K Fold cross validation, the data is divided into k subsets. Now the holdout method is repeated k times, such that each time, one of the k subsets is used as the test set/ validation set and the other k-1 subsets are put together to form a training set. The error estimation is averaged over all k trials to get total effectiveness of our model. As can be seen, every data point gets to be in a validation set exactly once, and gets to be in a training set k-1 times. This significantly reduces bias as we are using most of the data for fitting, and also significantly reduces variance as most of the data is also being used in validation set. Interchanging the training and test sets also adds to the effectiveness of this method. As a general rule and empirical evidence, K = 5 or 10 is generally preferred, but nothing’s fixed and it can take any value.

Stratified K-Fold Cross Validation

In some cases, there may be a large imbalance in the response variables. For example, in dataset concerning price of houses, there might be large number of houses having high price. Or in case of classification, there might be several times more negative samples than positive samples. For such problems, a slight variation in the K Fold cross validation technique is made, such that each fold contains approximately the same percentage of samples of each target class as the complete set, or in case of prediction problems, the mean response value is approximately equal in all the folds. This variation is also known as Stratified K Fold.

Above explained validation techniques are also referred to as Non-exhaustive cross validation methods. These do not compute all ways of splitting the original sample, i.e. you just have to decide how many subsets need to be made. Also, these are approximations of method explained below, also called Exhaustive Methods, that computes all possible ways the data can be split into training and test sets.

Leave-P-Out Cross Validation

This approach leaves p data points out of training data, i.e. if there are n data points in the original sample then, n-p samples are used to train the model and p points are used as the validation set. This is repeated for all combinations in which original sample can be separated this way, and then the error is averaged for all trials, to give overall effectiveness.

This method is exhaustive in the sense that it needs to train and validate the model for all possible combinations, and for moderately large p, it can become computationally infeasible.

A particular case of this method is when p = 1. This is known as Leave one out cross validation. This method is generally preferred over the previous one because it does not suffer from the intensive computation, as number of possible combinations is equal to number of data points in original sample or n.

Cross Validation is a very useful technique for assessing the effectiveness of your model, particularly in cases where you need to mitigate overfitting. It is also of use in determining the hyper parameters of your model, in the sense that which parameters will result in lowest test error. This is all the basic you need to get started with cross validation. You can get started with all kinds of validation techniques using Scikit-Learn, that gets you up and running with just a few lines of code in python.

 

Nifty

Nifty can shed 18 points at opening: Maximus Securities

Trading of SGX Nifty futures on the Singapore stock exchange indicates that the Nifty could lose 18.5 points at the opening bell, says Maximus Securities.

 

Maximus Securities’ Daily Report:

F&O Outlook:

Nifty PCR-OI has increased to 1.51 from 1.44. The rise in the ratio may be due to increase in PE of 10150 and decrease in CE of 10100. PE of 10100 and CE of 10200 are the highest number of contracts traded.

Opening for the Day:Trading of SGX Nifty futures on the Singapore stock exchange indicates that the Nifty could lose 18.5 points at the opening bell.

Disclaimer: The views and investment tips expressed by investment experts on moneycontrol.com are their own, and not that of the website or its management. Moneycontrol.com advises users to check with certified experts before taking any investment decisions.

 

 

Photoshop

Real photographs fade over time, but not evenly across the color spectrum.

• Create a new Hue/Saturation layer and change the blending mode from Normal to Saturation
• Check “Colorize” at the bottom of the adjustment window and set the Saturation to about 15, Lightness to about -28.
• To lower the contrast of the image, create a new Curves layer above that Hue/Saturation layer and raise the leftmost point (the black point) to about input 0, output 20.

The 10 best new features of iPhone X

Super Retina Display

Apple’s first iPhone with an OLED display is finally here, and the Super Retina Display is a sight to behold. It measures 5.8 inches diagonally, and it features a pixel density of 458 ppi with a 1,000,000:1 color ratio. It’s also a True Tone screen, which means it automatically adjusts its color temperature based on the lighting you’re in at any give time.

No Home Button

We knew this one was coming, of course, and Apple has replaced all of the home button’s functionality with gestures. For example, a swipe up from the bottom brings you to the home screen. Or, you can swipe up from the bottom and pause to open the app switcher. Ditching the home screen allowed Apple to produce a phone with an all-screen front, and it’s a welcome change.

Build

Apple’s iPhone is constructed entirely of sturdy glass and stainless steel. It comes in black and white, and the stainless steel polished to match the color of the phone.

Face ID

Face ID is an enhanced facial recognition feature that utilizes Apple’s new True Depth camera system. It features eight different cameras and sensors that combine to instantly recognize the owner’s face. The new A11 Bionic chip features a built-in neural engine that powers the system. Importantly, the system still works if you’re wearing glasses, if you change your hair, or even if you grow a beard. Low light also isn’t a problem, since there’s an infrared element.
Face ID will work for unlocking, Apple Pay, and with any third-party apps that implement it, just like Touch ID.

Animoji

The iPhone X’s new True Depth camera system also enables a fun new feature called Animoji. There are a dozen different animated emoji to start, and once you send them they mirror your own expressions and movements.

Cameras

The iPhone X includes a new dual-lens camera system on the back of the phone. It has dual optical image stabilization, making it just the second smartphone ever to feature dual OIS. The cameras still have 12-megapixel sensors, but they feature a ton of enhancements to improve color reproduction and reduce noise.

New Portrait Mode

Portrait Mode is also enhanced, with a new portrait lighting feature that lets you add lighting effects to your Portrait Mode shots. But it’s not just the rear cameras that get exciting new features related to depth effects. Around front, the True Depth camera also lets you take selfies in Portrait Mode!

A11 Bionic Chipset

64 bits… 6 cores… new Apple-designed GPU… new ISP… it’s a beast. You can see benchmarks  Prepare to fall off your seat.

Battery Life

Despite the smaller housing, Apple has somehow managed to increase battery life by 2 hours! Sadly, that’s compared to the iPhone 7, not the iPhone 7 Plus.

Wireless Charging

Fiiiiiinally. Apple’s new iPhone X supports Qi wireless charging so it works with just about all the equipment that’s already out there. On top of that, however, Apple has a new charging mat that’s capable of charging an iPhone X, an Apple Watch, and AirPods (with an optional new wireless charging case)… all at the same time on one mat!

Excel Function - VLOOKUP

VLOOKUP Function

Have you ever had two sets of data on two different spreadsheets that you want to combine into a single spreadsheet?
For example, you might have a list of people's names next to their email addresses in one spreadsheet, and a list of those same people's email addresses next to their company names in the other -- but you want the names, email addresses, and company names of those people to appear in one place.
I have to combine data sets like this a lot -- and when I do, the VLOOKUP is my go-to formula. Before you use the formula, though, be absolutely sure that you have at least one column that appears identically in both places. Scour your data sets to make sure the column of data you're using to combine your information is exactly the same, including no extra spaces.
The formula: =VLOOKUP(lookup value, table array, column number, [range lookup])
The formula with variables from our example below: =VLOOKUP(C2,Sheet2!A:B,2,FALSE)
In this formula, there are several variables. The following is true when you want to combine information in Sheet 1 and Sheet 2 onto Sheet 1.

• Lookup Value: This is the identical value you have in both spreadsheets. Choose the first value in your first spreadsheet. In the example that follows, this means the first email address on the list, or cell 2 (C2).
• Table Array: The range of columns on Sheet 2 you're going to pull your data from, including the column of data identical to your lookup value (in our example, email addresses) in Sheet 1 as well as the column of data you're trying to copy to Sheet 1. In our example, this is "Sheet2!A:B." "A" means Column A in Sheet 2, which is the column in Sheet 2 where the data identical to our lookup value (email) in Sheet 1 is listed. The "B" means Column B, which contains the information that's only available in Sheet 2 that you want to translate to Sheet 1.
• Column Number: If the table array (the range of columns you just indicated) this tells Excel which column the new data you want to copy to Sheet 1 is located in. In our example, this would be the column that "House" is located in. "House" is the second column in our range of columns (table array), so our column number is 2. [Note: Your range can be more than two columns. For example, if there are three columns on Sheet 2 -- Email, Age, and House -- and you still want to bring House onto Sheet 1, you can still use a VLOOKUP. You just need to change the "2" to a "3" so it pulls back the value in the third column: =VLOOKUP(C2:Sheet2!A:C,3,false).]
• Range Lookup: Use FALSE to ensure you pull in only exact value matches.

In the example below, Sheet 1 and Sheet 2 contain lists describing different information about the same people, and the common thread between the two is their email addresses. Let's say we want to combine both datasets so that all the house information from Sheet 2 translates over to Sheet 1.

So when we type in the formula =VLOOKUP(C2,Sheet2!A:B,2,FALSE), we bring all the house data into Sheet 1.
Keep in mind that VLOOKUP will only pull back values from the second sheet that are to the right of the column containing your identical data. This can lead to some limitations, which is why some people prefer to use the INDEX and MATCH functions instead.

Earn Money Online

18 Ways to Earn Money Online

Are you looking for the ways to earn money online? Did you try to make money online before but did not get success?

Then no need to worry anymore!

Because we have already trained more than 70000 people across the world & they are successfully making $200 to $2000 (more than INR 12,000) per month.

We are showing you below some of the best ways to earn money online. You can also download our training package which will help you to grow your income very fast.

And yes, everything in this website is Absolutely Free & Without Investment.

 
Check some of the best ways below & start immediately-

1. Earn from PTC sites

If you are trying to earn money online & need only small extra income less than $200 (Rs.12,000) then PTC sites are the best way to start.
Here you need to click & read the advertisements for 10 to 3o seconds & get paid for each & every advertisement you view.
There are many sites where you can register & make money by reading ads. All sites are free & there is no investment at all.
You can check this list of 5 best PTC sites, signup & start earning.

2. Earn with GPT Sites

To add more income, you can also join GPT sites where you can earn money by taking small surveys, watching videos, playing games & doing many more activities.
We have worked on number of GPT sites but we will recommend only 3 sites which pays their member on time. You can receive your payment by PayPal, cheque or bank transfer.
Check GPT sites here.

3. Become a Captcha Solver

If you have more time then you can add further income in your pocket by working as a captcha solver. This is the one of easiest way to earn money online.
As a captcha solver, you need to read the captcha images & type the exact characters. You need to be very fast in order to earn better income.
You can get paid up to $2 for every 1000 captchas you solve.
If you are interested in this then you can check this list of 10 best captcha entry sites.

4. Earn Money from Survey

Here you can make money by completing small surveys which takes 5 minutes to 30 minutes depending on the requirement of a particular company.
You need to write your feedback & opinion in a survey. You just have to select your choice from the question & there is no need to write anything.
You can make $1 to $20 depending on the length of the survey, your profile & the country you are living.
Visit here to join 20 best survey sites & to know more about online surveys.

4. AdSense & other Ad network

Although this one is the most favourite in my list but I put this in #4 because its not as easy as other 3 above & it takes time to make money from Google AdSense.
You need a website (which anyone can create now a days) & some tricks to bring the traffic on your website so that you can earn money from AdSense & other ad network.
We have prepared one of the best course on AdSense earning which thousands of people in India & all over the world have used & now they are earning $200 to $1000+ per month.
This training course is absolutely free & you can download after signup here.

5. Earn with Affiliate Marketing

If you are serious about earning money online & you are a hard working guy who wants to make big income then affiliate marketing is for you.
There is more scope for affiliate marketing than before because of the high growth of online shopping.
There are hundreds of online merchants like Flipkart, Amazon, eBay, Clickbank, CJ etc. where you can signup & promote their products.
In affiliate marketing, you are simply helping customers to buy the right product by creating a simple website & in return you can earn 4% to 20% commission.
You can signup free here so that we can send you one of the best guide on affiliate marketing that can help you to earn great income.

6. Become a freelancer

Freelancing is another popular way to make money after AdSense & affiliate marketing. As a freelancer, you can work with small or big companies on a temporary basis & provide them your services.
Freelancers can make $500 to $2000+ per month depending on the type of skills you will use as a freelancer.
You can work as a content writer, web designer, graphics design or provide services like SEO, data entry & many more.
There are dozens of popular websites like Elance, Freelancer.in, WorkNHire, Upwork, People per Hour etc. that can give you the ready platform with ready clients.

7. Virtual Assistant

A virtual assistant is like a personal assistant who can earn money by working online for someone without being physically present.
He can do variety of tasks like taking care of websites, counselling, writing & proofreading, publishing content, marketing, coding, website & app development, research etc.
There are dozens of companies like HireMyMom, MyTasker, Zirtual, uAssistMe, 123Employee where you can signup for virtual assistant work.

6. Writing Job

Writing is another better way to earn money on internet through writing different types of content. You can write for blogs, companies, institutions, individual people etc.
Different types of writers get paid differently. Normally people get paid $5 or more for 500 words content.
You can go to the sites like Elance, iWriter, WriterBay, FreelanceWriting, TextBroker, ExpressWriters.com, FreelanceWritingGigs.com to find the content writing jobs.

7. Web design

If you have idea of web design & development then you can make money online by taking order from the customers who are looking to develop their website.
If you don’t have idea then you can take the training & then start this because this field has got a great potential. Either you can promote this offline or create your own website and promote 0nline.

8. SEO

This is one of the most popular business online & if you have idea of SEO then you don’t have to worry about making money online.
Companies spend hundreds to thousands of dollars every month on SEO so that their website can get on the top of Google for their business keywords.
You need to take the training from a popular institute like SEOTrainingCourse.co.in where you can learn practical SEO tips & implement the same to rank different types of sites.

9. Micro-working

If you are a kind of person who want simple ways to earn money online & not mare than $200-$300 (Rs.15000) per month then you can become a micro worker.
Here you can work on variety of different tasks like identifying an object, rating & commenting on different sites, visiting some websites, finding contact details, doing small research, writing small articles etc.
There are many websites like mTurk, MicroWorker, SEOClerk, ClickWorker, GigWalk where you can work as a micro worker & earn extra income.

10. Seller on Fiverr

Fiverr is a place where you can do any service for $5. You can visit the website Fiverr.com & check which type of service you can do on Fiverr.
You can become a seller on Fiverr & create your gigs where you can tell people that you can do so & so for $5.
People see your gig & if they like it, they will order your service. Even if you complete 1 gig a day, you can make $150 or Rs.9000/- per month.
Our training material on Fiverr can help you to grow your business & you can make great money from Fiverr.

10. YouTube Channel

You go anywhere or do anything, if you love shooting videos on all these occasions then there is a great scope for you to earn money from YouTube.
All you need to do is upload the videos on YouTube & become a YouTube partner. For each & every view, you will get paid.
Sometime if any of your videos become viral then you can make huge money.

11. Become an online seller

Online selling is not like traditional selling. Here you just need to become a seller on some of the top shopping portals like eBay, Amazon, Flipkart, SnapDeal etc. & list the products you want to sell.
You can roam around your city & check for the best products you can sell on these sites. You need to try the best products that you can sell at lower than market price.
Trust me, its easier than your thought. Only thing you need to do is take action.

12. Domain Trader

Domain trading is another high profit business you can do online. But here you need some investment for buying the domain.’
You must be an expert OR you should get detailed knowledge before you start this business. You can buy domains from GoDaddy or other domain registrar for less than $10 & sell in future to the needy person for hundreds of dollars.
Your skill here is to identify great domains that are not booked yet & companies in future can try to buy that domain.
When companies don’t find the domain of their choice, they contact the domain owner for the deal & it’s in your control to fix the price.
You can even put your domains on auction so that people can buy directly at your desired price.

13. Website flipping

Like domain trading, website flipping is also a hot business to earn money online. Here you don’t deal with domains but websites.
You have to create a website, work on it for 3-6 months or more so that you can start making money from the websites.
After earning for 2-3 months, you can put that site on auction on Flippa & other platforms. You can easily get 15-20 times price of your monthly earning from that website.

14. Provide training & consultancy

If you possess some good skills & love to teach then you can start a training or consultancy business online.
You can provide training on English or any computer course, provide consultancy on vastu, any technical topic or if you are a doctor can provide consultancy for treatment etc.
There are number of things you can teach online. You can promote your business by creating a website or a Facebook page or by placing ads in classified sites etc.

15. Stock & Forex Trading

Stock trading & forex trading is a very lucrative way to make money for those who has good idea of the market.
There are number of free or paid courses available on internet that can train you for online trading. You can even read newspaper like Economic times or watch TV channels like CNBC to become more expert in the field.
Its risky to enter into this market without sufficient knowledge.

16. Earn money from your smartphone

There are various apps that can make you some small money by doing & completing some simple tasks on your Smartphone.
There are at least 10 apps that can earn you some extra income in the range of $100-$150 a month. You have to take simple surveys, complete offers by signup on other websites, play games, watch videos etc.
We will show you the list of these apps after you signup for our training.

17. Sell photos online

This is another use of your smartphone. You can take high quality images of nature, places, people, things, dishes, homes etc. & sell them online.
There are number of big sites like Shutterstock, Fotolia, , iStockPhoto, Photobucket where you can submit your photos.
Whenever some customer wants to purchase your photos, you will get paid as per the price you fix. You can get paid multiple time for the same photos.

18. Sell old stuff on OLX or Quikr

I am sure there may be number of things in your home that are lying unused for months & if you take little efforts, you can earn some good money.
You just need to do 2 things, i.e. find out all the items that you are no longer using, take high quality photos of these items from different angles & list these items on OLX & Quikr for sale.
Not only this, you can also ask your friends & relatives for selling their old stuff. You can help them selling these items & make some commission.
So these 18 ways can provide a perfect answer for your query ‘how to earn money online” & yes, you can shoot an email to us in case of assistance.

Trick - 1

Algorithms

   
Answer:  2   (Count the circles in each digit)

 

English Grammar A - An - The

English Grammar  A - An - The 

 

It is so common that people get a, an, & the confused. We will clear that problem up right now, so you will understand when to use a, an & the.

A , An & The - Indefinite Article - are used with non-specific singular nouns

• I want a pen. - any pen
• I am going to rent a car. - any car
• I want an apple. - any apple
• I need a car. - any car

The - Definite Article - is used with singular & plural specific nouns or nouns that are one of a kind

• I want the green pen. - specific pen
• The girls want to rent the small car. - a specific car
• I want the red apple. - a specific apple
• We are going on the red boat. - a specific boat