Techniques for random sampling and avoiding bias | Study design | AP Statistics | Khan Academy

Techniques for random sampling and avoiding bias.

AP Statistics on Khan Academy: Meet one of our writers for AP¨_ Statistics, Jeff. A former high school teacher for 10 years in Kalamazoo, Michigan, Jeff taught Algebra 1, Geometry, Algebra 2, Introductory Statistics, and AP¨_ Statistics. Today he's hard at work creating new exercises and articles for AP¨_ Statistics.

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[kavishkartha]

I have a math test tomorrow and I watched this since I had no clue what a sample was. This was very helpful. I completley understand what a sample is.

[bikey]

I genuinely felt lucky that I got access to these incredible lectures of khan academy. Thanks to internet. Otherwise i would have never imagined that i will get the world-class education back in my home here in Himalayas, Nepal. We just got internet this year and that had opened lots of ways to get useful knowledge.

[michellenguyen]

Whoever disliked this is jealous of how Genius he is.

[kayagrace]

Teachers. 👏 let. 👏 him. 👏 explain. 👏 it. 👏

[fatimamosqueda-juarez]

You made the concepts easy to grasp! thank you for your help

[jody]

Wow I have an exam tomorrow and If I pass then props out to YOU!

[londonchandler]

Oh my god thank you for making this so simple for me! Second time taking this statistics class and I hope I pass this go around!

[justindelove]

What is best depends a lot of how often you survey. In the long run a random selection from the whole population should be the most useful as it will show trends very clearly.. For a one off survey I would go with clusters, which give a good snap shot but is less likely follow trends accurately, because the randomly selected clusters may cancel each other out. Stratified is the safest choice as it broad enough to show trends, and narrow enough to make a quick reading. By narrow I mean it less subject to periodic unusual peaks and troughs of randomness. Really girls and boys should be filtered as whatever method is used the division can be made afterward. If show significant deviation from the whole that can be taken into account. The same is true of other pairs of Opposition, older younger, richer, poorer etc. So my ideal would be to brew up a random survey of the whole regularly and then filter the results to taste.

[mollycarlisle]

Very helpful! Thank you for taking the time to make this.

[jobogads]

Jolanda Bostick
MGF1106
This video helped me understand how to conduct surveys

[MrKolbersTeaching]

Good stuff! An important aspect of modern data collection.

[angmo-]

thanx for helping out, it'was really v. informative..!

[olaoweigbendu]

Thanks alot for the lecture. Do we have anything like balloting technique as a way of sampling randomly?

[amyf]

Jeff can you please be my statistics tutor?!

[salama]

I have an exam tomorrow and I am having a mental breakdown because I can not get it

[rosazaid]

I have my exams after a month and I've recently come across a question relating to this, " describe how you would carry out quadrat method" pls answer this for me,

[javiermediavillavegas]

I don't understand the statement that simple sampling can get a sample that is not indicative of the population because there could be a group that is "over represented". Do you mean because only 100 samples were taken? Otherwise, in my view, if 1k samples or above were taken, that "over representation" would not be such but the actual population is distributed like that.

[syedmaharabsshah]

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[Dr.Ahmednafis]

please use white background. and that is comfortable for eyes.