Statistics 101: Is My Data Normal?

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Statistics 101: Is My Data Normal?
Many statistical techniques assume that the underlying data is normally distributed. What simple techniques can we use to test this assumption? In this presentation we will briefly discuss the following tools to determine if our data is "normal" free of excess skew and/or kurtosis:
Histograms
Stem and Leaf Plots
Box Plots (Box and Whisker Plots)
P-P Plots
Q-Q Plots
I do not go into how these tools are calculated. This is merely an introduction to common preemptive visual techniques to determine the normality of a data set. Enjoy!
My playlist table of contents, Video Companion Guide PDF documents, and file downloads can be found on my website: www.bcfoltz.com

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8 авг 2024

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Комментарии : 151

@sahb8091 8 лет назад

I refer my friends and my girlfriend here whenever I'm stumped by statistics. I also appreciate the encouraging words at the beginning, you sir have that rare quality of encouragement that sounds genuine rather than condescending. Thank you for all your hard work.

@mikeguastaferri4943 10 лет назад

Brandon, I suspect I fall outside the 'target audience ' that you imagine when you post these videos. I am a sixty-something machinist using S.P.C to try to control a C.N.C milling process. I found, much to my chagrin, that I need some grounding in statistics to draw useful inferences from my data. Your videos were the best introduction to statistical thinking I found on the Web. Good Work, in every sense of the words. Thanks very much for doing these.

@rhoninpowers 7 лет назад

Mike...I could not agree more. Through Brandon I feel like I am rediscovering Statistics again...but now empowered to explore my own interests within what's being taught and my own curiosities.

@ricardoafonso7563 3 года назад

. Just turned 60 . Look at the world around........ never too late to learn .

@pradeepcghai 9 лет назад

You are such a fantastic teacher .You explain so well even the finest details are clearly understood.Thankyou soo much . Please keep on supporting with your good work. God bless you !

@BrandonFoltz 9 лет назад

+PradeepC Ghai Thank you so much! I've been fortunate to have great teachers my entire life. I just try to stand upon their shoulders.

@buiyin 6 лет назад

your intro make me feel calm because i'm struggling with spss right now.

@gmailaaaa 8 лет назад

Your videos are awesome. But kindly arrange them properly in playlists so that we can follow the videos sequentially.

@elizabethbright6890 4 года назад

Wow! You made me want to cry! I'm struggling with an online nursing research course and your introduction was the best peptalk I could have received! Thank you!

@rigae2 2 года назад

same here

@BrandonFoltz 11 лет назад

Thank you so much for your comment! :) I am very glad you found it helpful. All the best, B.

@AnneCalie 6 лет назад

Hello, I just wanna say you are an excellent teacher and a wonderful person. not only are your explanations very easy to understand, but your motivational speech is inspiring. Thank you for sharing this!

@Surya42930 11 лет назад

Your insight towards making the data visual & then trying to explain the very purpose of the concept is amazing...You are the best mentor I have found in my life....Thank you Brandon

@rajatbhatheja356 6 лет назад

I am not sure who are these 18 people who disliked this video. You are an awesome teacher. All your videos are great.

@zenamarwan2932 6 лет назад

Thank you so much ..you are so supportive and encouraging.. I am so grateful to your kindness and great way of explaining all of these terms.

@celestegoodnight3387 9 лет назад

very helpful for someone like me trying to gain a foundation of knowledge to build on!

@MusafirHoonYaro Год назад

Very good video with very clear explanation and effective visuals. Thank you for taking the time to make these videos available.

@vanglequy7844 10 лет назад

Hi Brandon, A lecture on how to find the best distribution for any dataset would be very interesting. Of course background of the dataset is more important to determine which distribution it follows, but finding best match distribution is still good for confirmation or exploration on not well-known data source.

@BrandonFoltz 11 лет назад

Thanks Rahul! I am working on a new one right now on 2-Way ANOVA. With a full-time job and the complexity of the topics and work I put into them, they take a bit longer to make at the moment. But I am working on it! :) Best, B.

@NandishPatelV 2 года назад

For the first time I understand the different graphs in relation to probability. Thanks! KeepSmiling 😊🌺

@cybertirtha 5 лет назад

Hi Brandon. You are a star. Thank you for your willingness help people like us. I like and appreciate the clarity of your facts/observations presented here.

@cybertirtha 5 лет назад

Hi Brandon. Just a small query and will appreciate your observations. I have a large dataset for statistical analysis (specifically for ANOVA and linear regression) and currently wondering whether a visual idea of the p-p plot of the same is enough to analyze their normality. Is there any threshold statistic (a value) to consider for the plot to confirm normal distribution of the data? Many thanks.

@irishlobster 2 года назад

Yes, thank you for that wonderfully motivating intro. You have no idea; my struggles.

@mhalgas 10 лет назад

Thanks a lot. Veeery useful, simple and clear. I wish i had had a teacher like you in my lycee. Good work.

@deyanirabalboaarteaga8956 3 года назад

Thanks for the great content and your encouraging words!! You are making me like statistics more.

@beautyisinmind2163 2 года назад

best channel to learn statistics for Machine learning

@mohammadalitorabi5626 7 лет назад

impossible to teach better than this

@andrewkinsman6137 10 лет назад

Great series. I'm not sure why this video has been assigned to PL03 though. You start by mentioning all the other videos on the various probability distributions that you have made, all of which are in PL05 and PL06.

@nebyouyonas3496 10 лет назад

thank you Brandon for research around the world who needs more statistics your product is useful. thank you again and keep it up

@praveenshahapurmath834 5 лет назад

Excellent Lecture. Thank you so much for your videos Sir.

@guptagsaurabh 7 лет назад

God bless you! Brandon you are better than Ivy league professors who have their videos uploaded. After all Teaching is more about communicating rather than demonstrating technical expertise ;)

@dhavaldwivedi Год назад

Very nicely explained. Thank you sir.

@mohammadal-abbasi7247 5 лет назад

Great Video man. Clear and Informative. Thanks!

@andrecae1 4 года назад

Great content and explanation. Thanks!

@Denisediane1 11 лет назад

You are the best explanation I have found. Great job.

@alxms10 4 года назад

Thanks very much for your videos and making our life easier. Two quick feedback points: The first video (Understanding Z-scores) in your list should be at number 4 on the list The last (Is My Data Normal?) should probably move to another playlist (I guess at end of PL06 but please check as you are most familiar wit your lists) Thanks

@layondamillsap1580 6 лет назад

Thank you so much for posting this. It was very helpful

@aboalhoss5600 8 лет назад

Thanks for your videos, it helps :) and is easy to go to.. Keep up the good effort with sharing your knowledge.

@nislau03 8 лет назад

Clear Explanation! Thank you Brandon.

@jakobmelbye3887 6 лет назад

Thank you for the video, and the nice words in the intro :)

@Mikeybikey88 9 лет назад

Thank you! Your videos are a GODSEND!!!!

@joshuah2786 11 лет назад

Brandon Foltz: great video! working on my M. S in biology and these videos are really helping me get through the initial stage of basic data analysis for my data!

@vishalsonar1510 2 года назад

its been 8 years how are you ??

@Lukegi88 8 лет назад

Great video! Please keep helping us.

@FPrimeHD1618 6 лет назад

I subscribed just because of that motivational speech at the beginning...Now to watch the lecture.

@ranjitpalsingh2787 8 лет назад

Agree With Mr Pradeep C Ghai. Watched your video today Only. It is great.

@zaireadams100 8 лет назад

I really like the way you explain material.

@debiprasadmohanty8707 9 лет назад

Sir I m a big fan of urs. Really thankful to you. But I find it a lil difficult to search in particular ur videos on a few topics.. U r the one who taught me stats...god bless you...

@M0NiiSiiA 10 лет назад

Thank you for your help! Definitely helping me right now with my stats class!

@SMHLK218 5 лет назад

Best video on this topic!

@aureliohess9349 4 года назад

The best stats teacher EVER!!!

@marcymiller7510 6 лет назад

Thanks for the encouraging comments! They do not go unnoticed :).

@farmad100 4 года назад

Excellent explanation of normality concept

@dribrahimel-nahhal2477 3 года назад

Thank you! Simply Awesome videos. Pretty excellent explanation.

@rajalb 2 года назад

That intro made my day! ❤

@justinatuulikefonangolo5509 4 года назад

Thank you very much for this informative video.

@RebeccaDavison1 11 лет назад

Hi Brandon, I never leave messages usually but I just had to say thank you because this video is excellent. Very best wishes, Rebecca :)

@mohsentakesh2524 5 лет назад

Thank you very very much for this great video.

@marialaureano3334 6 лет назад

You're so sweet! The intro is awesome, I had to hear that m, thank u😣

@moonprism10 11 лет назад

I second this question! What does one do next if the data is not normally distributed?

@JoarderMdSarwarMujib 9 лет назад

Great video for ppl like me who have shallow knowledge about the topic.

@BrandonFoltz 9 лет назад

Joarder Md Sarwar Mujib Thank you so much! Glad to have helped deepen your knowledge a little bit. But you took the time to watch and for that I am very appreciative. Best, B.

@Malzen66 4 года назад

Great work! Could you consider doing a video on half or folded normal? How do you work with bonded data i.e 0 and above? Thanks for your help

@adelushka 11 лет назад

such an inspirational introduction

@MrSaurabharena 7 лет назад

Simply Awesome.

@valor36az 5 лет назад

Sir thank you for all these videos

@emiltimlin5777 6 лет назад

Really like your videos!! You say in this video that you will do a seperate video for p-p plots and q-q plots but i can`t find them :/

@viggojuhl2471 7 лет назад

Great explanation. You speak loud and clear which made it very easy to understand. Consider cutting some of your introduction. It was very long. Otherwise great job.

@romanvasiura6705 Год назад

Thank you!

@diegopedreros9363 7 лет назад

Brandon, thanks very much for the videos, do you have one on percentiles?

@themortgagechic_ca 7 лет назад

Thanks soo much Brandon!

@jongcheulkim7284 3 года назад

Thank you.

@francesco.bellomo 8 лет назад

Hi Brandon, you videos are great! May you let me know where I can find the Statistics 101 PL02?

@chryssokonofua1109 9 лет назад

Nice video. Thank you.

@utubemania9079 5 лет назад

You saved me bro.Thanks a ton from India.

@BrandonFoltz 5 лет назад

You are welcome! But you saved yourself by pressing the play button. 🤟👊 Stay strong and keep learning. You got this.

@khan044 9 лет назад

Thanks for sharing

@EdgarMartinez-ub2oo 5 лет назад

i love you man. foreal foreal. God bless you!

@pinkyc7328 7 лет назад

You r the Best!

@_Chafia 6 лет назад

Thanks a lot it's very helpful.. a question please..what do to if we have a bimodal distribution? can we make an AOV separately for each population.. And please can you make tutorials with R...Thanks!

@dicksonadjarani1921 2 года назад

THANK YOU

@zeinhaddad2937 7 лет назад

Do you have a PL02 somewhere? I feel that I have missed some lessons but I cannot locate it on your playlists list! Thanks for your helpful videos.

@anitarebecca6009 6 лет назад

VERY USEFUL.

@shivaprasadreddy463 9 лет назад

Excellent!

@BrandonFoltz 9 лет назад

+Shivaprasad Reddy Thank you!

@laaxmi1966 6 лет назад

very good session

@mohamedabdelmawla4811 4 года назад

thanks a lot .

@tonyrandall3146 5 лет назад

Thanks

@MusafirHoonYaro Год назад

Hello Brandon - do you have a video dedicated to q-q plots in the context of a simple linear regression between one independent variable and one dependent/response variable? Thank you.

@luisangelgalaviz4950 6 лет назад

Pretty good, thank you

@CliffDaSikk 11 лет назад

thx, this helped me a lot !

@BrandonFoltz 11 лет назад

Hello! Unfortunately there is no easy answer as for what to do when the data is not normal (or why it's not normal in the first place). It could be because the population is not normal. It could be a sampling or data entry error (it happens). The sample data could be put through a transformation such as logarithmic. Different procedures have different tolerances for non-normal data. Non normal data is fine, it just depends on what you plan on doing next.

@apamwamba 5 месяцев назад

Do you have a video on shapiro , kolmogrov tests etc.. i like the graphical inspection of the data

@nazda529 4 года назад

the most perfect video

@newyorksharp 10 лет назад

Great job again!! James N Zeris, CPA

@cococnk388 2 года назад

great thanks

@alextheo7862 11 лет назад

Well I gotta say that you helped me a lot with this video. Im on my Bachelorthesis and I write some critical words about the normal distribution and daily stock returns. Now I plotted a lot of graphical stuff but i need some statistical tests. Do you have videos about the KS-Test, JB-Test and Hurst-Exponent. (interpretation and how it works) I have no statistical software. I have to work with excel. thanks regards from germany!

@IvCastilla 11 лет назад

Hello Brandon, the fact of mean=media=mode can be used as guide to find what distribution follow our data ? I mean, as a first step for know what distributions we must consider or not consider? If yes, what can be the tolerance between them? Thank you for all your videos, they are very good and useful. Ivan Castilla

@Venturosoc 11 лет назад

Thank You!!!

@nawalal-haidari92 9 лет назад

thanks a lot a lot , you are amazing !!

@sangameshks6250 7 лет назад

Very nice

@shaewicks 8 лет назад

start video by making me want to cry? >:(

@MayankKumar_DataScience 7 лет назад

nice tutorial : )

@authenticspirituality 7 лет назад

what kind/type of variables are we testing by using normality test please? i have so many and dont know which ones i need to test test. thanks

@Denisediane1 11 лет назад

I am also looking for very simple 101 Statistics like these. Do you have a list of "order" of the video that I could watch. (I am 61 and just starting my PhD, it has been a long time since I had to do statistics.

@delcapslock100 10 лет назад

Brandon, I hear two mantras in stats that appear to oppose each other, and was hoping you could clarify: one is that it is very important to determine whether your data is normal, and the other is that because of CLT, it doesn't matter what kind of distribution the data comes from because the sampling distribution of the sample mean will be normal (given adequate sample size, etc.), Am I misunderstanding something? thanks, Paul