Variance and Standard Deviation: Sample and Population Practice Statistics Problems

Рет қаралды 1,170,986

8 жыл бұрын

For more success with variance and standard deviation problems, you can checkout the book I used for reference, Schaum's Statistics Outline - amzn.to/2yeUaDk.
Variance and Standard Deviation are all statistical ways of measuring variation. We'll take a look at how to solve practice statistics problems for sample variance, sample standard deviation, population variance and population standard deviation by hand using just your calculator. In our problem we'll take a look at ages of kids at a birthday party. I also mention how to make meaning of this data if they were points somebody scores in various basketball games. Hope that helps.
*More practice statistics and probability videos*
+ Average (Mean, Mode, Midrange): • Mean, Mode, Median, Mi...
+ Variance and Standard Deviation: • Variance and Standard ...
+ Frequency Tables: • How to Create Frequenc...
+ Hypothesis Testing: • Point Estimates and Co...
My goal is to help my students flourish in all aspects of their lives. Here are some recommended tools to help you find success.
*Success in Statistics and Probability*
+ Statistics Demystified - amzn.to/2yDhH2m
+ Probability Demystified - amzn.to/2yWm70k
*Success in School*
+ How to Win at College - amzn.to/2yeQjGq
+ Get Better Grades by Studying Smarter! - 874bf9z88-y64q27254i133i6q.hop...
+ How to be a Straight A Student - amzn.to/2zd7vui
*Success In Life*
+ Goal Tracking System (web-based) - d6a218199dz69xd106ogz9s470.hop...
+ Innovation & Creative Thinker (skill employers love) - amzn.to/2zdQUq3
+ Developing a Mindset for a Fulfilled Life - amzn.to/2xwVzqd
The videos I post on KZfaq are primarily for my own college students, so I usually do not have time to respond to KZfaq comments. But, I'll do my best to respond when I can.

Пікірлер: 253

@Dee-ye2dk 5 жыл бұрын

When you have a full time job plus attend college full time but you find someone willing to give their time to teach others via KZfaq. Thank you for this video, currently taking stats in college.

@fernandomaron3498 6 жыл бұрын

It's funny. Sometimes we stay 2 hours in class watching professor explain how to calculate standard deviation and variance. At the end we don't understand very well. Here, 13 min is more than enough for me to understand and gain confidence. Anyway, thank you very much for the video.

@caseymaps4918 5 жыл бұрын

That's so true

@jasontutorials4809 5 жыл бұрын

Spend time in an hour and a half lecture, and still don’t understand anything, watch a 13 min video or even shorter, and miraculously understand it...explain that

@stephenkiama4665 5 жыл бұрын

I agree with you

@KK-yt8qw 5 жыл бұрын

Stephen Kiama e

@sirhilmohamed1193 4 жыл бұрын

I seconded you.

@sayedalihaider7307 2 жыл бұрын

How hard could've it been for our teacher if he had just explained it this simple?! Thank you so much, man!

@angelicaibanez5327 4 жыл бұрын

I'm in Business Economics & Decisoin Science. Roughly over a month. I just understood your 13 min. video of the sample mean, variance, and standard deviation. Over my professor. I was struggling in finding the mean, variance and SD but i see now that is more simple then what I thought. THANK YOU!!!

@AndrewMcNeillMusic 6 жыл бұрын

What a brilliant communicator! Totally recommended. Look forward to checking out more of your videos

@dennisecallejas7185 6 жыл бұрын

ive been having a hard time understanding standard deviation and variance and am more of a hands on person when it comes to learning. Thank you very much this helped A LOT !

@hlalelemohale7296 4 жыл бұрын

Thanks, from South Africa here sir! I have been struggling to know, when to use denominator (n-1) or 'n', you explained so clearer than cristal. Thanks now I have peace of mind, you the bosssss!!

@elesahefner9155 3 жыл бұрын

Thank you soooooo much!! I spent a week trying to understand my online stats class and watched this video 1x and now understand perfectly. YOU'RE AMAZING!!!

@mbangetaheteng3419 4 жыл бұрын

sir i really appreciate the way you teaches on this topic, you give more clarity on statistic management concerning variation,thanks

@exploringim6191 4 жыл бұрын

That equation looked all kinds of terrifying before you explained what the letters were. I just stared at it in my text book not understanding a single word of it. Now I'm saved. Thank you!

@elirivera8880 2 жыл бұрын

Wow ! Great explanation.... I am currently taking an online class and read the book and had no idea because the formula was driving me crazy! Thank you!

@joyceguevara8302 4 жыл бұрын

This was very helpful to understand the formulas. He make it seem very simple to do it yourself.

@hanesmitter1469 5 жыл бұрын

I had forgotten this simple procedure and I totally couldn't remember Credits to you

@Name_idkk 3 жыл бұрын

Thank you so much. This really helped with my stat finals in a day.

@alejandrabradley8180 6 жыл бұрын

Thank you for the help, great example!!

@GrimFemme 7 жыл бұрын

You just saved my grade. Thank you.

@bismarkanloadey289 5 жыл бұрын

lol funny

@tahirhammond7032 5 жыл бұрын

Sofia yh true talk

@bismarkanloadey289 5 жыл бұрын

So where do u school?

@Leo-mh5mf 3 жыл бұрын

You alive?

@ahamedakmal7104 7 жыл бұрын

how will standard deviation of a set of discrete data change -when a value that is equal to the mean is added to data -when a value less than one standard deviation from mean is added to data -when a value that is more than one standard deviation is added to data?

@nurulainnajwasuhaimai4418 3 жыл бұрын

just know that before this I'd used a complicated formula to remember. u saved my time to memorise and understand this thing!!

@tavuzzi6955 6 жыл бұрын

Thank you for your video. It did help me a lot!

@enteryunion1673 3 жыл бұрын

My math teacher is not good as u sir simple yet easy to follow and understand each steps of the way.. thank u ...save. A lot of time and brain ...energy. .

@fabishkenya9263 3 жыл бұрын

great video.At least i have understood the difference between population and sample standard deviation

@elividal7202 6 жыл бұрын

super clear explanation

@nosiphosimelane5736 2 жыл бұрын

I really needed this lesson before my STAs exam

@Elviskiol-do7dy Ай бұрын

This explanation helps me understand very well 🙏🙏. Thank you sir🤝🤝

@tarikuamante4546 4 жыл бұрын

it is an interesting demonstration. you make it easy for us. thanks a lot statistic dojo

@afiacodlin3739 Жыл бұрын

i must say thank you and i so glad i came across your video. i really needed this clarification

@tamaraseid7413 6 жыл бұрын

I think this calculation is correct for population, but here since we have the sample of numbers so the denominator in the formula is supposed to be not n, but n-1 . Thank you for clear explanation.

@MathsclassKI 5 жыл бұрын

very clear good teaching

@gedeonkibambe9930 Ай бұрын

I know that you made that video since long time, but I just wanted to say thank you for that, thanks a lot;)

@mindy8331 2 жыл бұрын

Thank you for this video. Very helpful.

@louiscayohwe 6 жыл бұрын

I LOVE YOUR WORK SIR

@linetgachiuki3078 4 жыл бұрын

Great demonstration! I would like to be as clear as you are when I ever get to teach!

@statisticstuber6110 3 жыл бұрын

You can take any kind of statistics help at anderson.kevinnn0@gmail.com

@nomarseyer4551 5 жыл бұрын

simply done. Thank you

@penguin2106 7 жыл бұрын

thank you so much. it really helps.

@0069yj 4 жыл бұрын

Great work ... thank you

@jimvenniceatienda816 6 жыл бұрын

ty for this video, i know how to get the variance and standard deviation

@NoNamae0_0 2 жыл бұрын

bro ur a lifesaver.

@af5104 2 жыл бұрын

For the variance, you must divide by the total of frequencies. The square of the either of the STDEV.S and .P will not give you the variance which in most cases should be a decimal fraction.

@osenisuliat5041 4 жыл бұрын

Thanks so much, really helpful

@oolasaverio3756 5 жыл бұрын

please I need assistance for x bar when calculating mean, the symbol is missing in my computer

@smileyshine1163 2 ай бұрын

Super explanation Thank you sir

@tammymcfee9325 4 жыл бұрын

Thank you!!! I have been trying to do this for days... I have been trying to subtract the first set of x-x from the second set squared and I was always getting negatives...I was frustrated....

@kkurachannel2715 4 жыл бұрын

help... i'm cnfused with the z-score equations. how to know if a problem will use population ewuation or sample equafion..?

@sitinuradilahizzatimddaim2384 7 жыл бұрын

Thank you sir.

@yogeshpareek181 3 жыл бұрын

Realy great vedio sir thax for helping

@mrhq3153 4 жыл бұрын

Good explaination.

@lovemendez5406 4 жыл бұрын

I loved how you described it, I was able to comprehend through your work fast, but how do you do the frequency that goes in the beginning ? Anyone please let me know thanks 🤓

@abubakaryunusa2604 4 жыл бұрын

WE ADD ALL THE FREQUENCIES AND DIVIDE THEM BY FIVE(TOTAL NUMBER OF THE FREQUENCIES) TO GET THE MEAN WHICH IS 6.4

@----cp6xy Жыл бұрын

This video was so helpful 🙌

@amancabdi3035 5 жыл бұрын

thank you for helping us

@tobiasadams1504 4 жыл бұрын

Thank you kind sir. Blessings.

@user-kb6hl4kg6h 9 ай бұрын

Thank you i learn something that I didn't know before currently am from gambella region in Ethiopia county of Africa continent

@danizooo2129 4 жыл бұрын

can you please make a video on how to solve problems in statistics and scientific method badly need it for my psychological statistics subject

@mikaela_reads 5 жыл бұрын

THANK YOU SIR 💜

@toltap267 5 жыл бұрын

thank for your really thinking

@analync.torres625 2 жыл бұрын

I got it. 27.2 divide by 4 is equal to 6.8. Anyway, thank you for this video. I learn a lot. God bless☺️🙏🏻

@farrahkhan2160 5 жыл бұрын

Nice easy to understand

@angelanasto1068 6 жыл бұрын

Thank you so much !!

@user-fb3gb2vk4e 4 жыл бұрын

Thank you I'm understanding it

@nakasisara4400 5 жыл бұрын

I just like this class

@wotagetie1549 6 жыл бұрын

thank you for this video

@buchayjames6948 5 жыл бұрын

Thanks that's was really great

@dasbodh5799 3 жыл бұрын

Nice explanation 👍👍

@taranaali6025 5 жыл бұрын

Good explanation

@sunkarimourya5739 5 жыл бұрын

Yaaaa good sir and please make more videos on states sir it will help mee sir

@MrOusmane23 Жыл бұрын

he is just amazing

@veenahebballimath5913 5 жыл бұрын

Tnx for uploading this video

@Masteridea101 5 жыл бұрын

undestand that, the teahcer has explained the formula.. but how is this related to the initial series??

@lekpjedits18 4 жыл бұрын

Sir....plz help me to find the answer of this question : The mean and standard deviation of a set of 100 observations are worked out as 40 and 5 respectively by a computer which by mistake took the value of 50 in place of 40 for one observation. Find the correct mean and variance Plzz... bcz this is the most frequently asked question in our exams

@naumanshabbirawan4232 4 жыл бұрын

thank you so much dear sir

@zeyadmaeed6362 5 жыл бұрын

Thanks man 💓

@celinewalters66 5 жыл бұрын

Thank you!

@maheshwaripanuganti5889 3 жыл бұрын

Thank you so much

@n.g.6442 4 жыл бұрын

Why is it that when dividing some ppl subtract 1 from it like (n-1) whereas others just divide by n?

@koba3174 Жыл бұрын

How did the 27.2 over 4 became 2.607? Did you square root it? How did you exactly got it??

@nazmulislam3580 5 жыл бұрын

i like your classes very much

@kwadwoamoahjohn7640 5 жыл бұрын

pls can u go over it again

@ajayjackson7727 4 жыл бұрын

what is the standard deviation of the data set 30 0 0 ?

@lailauthman5454 5 жыл бұрын

It's very helpful, infact when I confuse in my reading (revision) I just visit this clip🙌 🌹🥀💐

@MikhaelAhava 5 жыл бұрын

I think this will help me thanks.

@AsgharKhan-bv2hc 6 жыл бұрын

Good job,weldone

@odogwuhenry 2 жыл бұрын

I like your explanation. But I have one problem. Before checking out your video, I had just read a section of a book explaining standard deviation. But in the book's formula, there was no (n-1) it was just (n) and the sigma sign was written in the formula. what is the "1" for and why? It's really confusing

@andersonprado1099 6 жыл бұрын

Thanks a million

@haleemahabulaimon8081 6 жыл бұрын

Thanks a lot 😍😍

@charlottewaller6269 4 жыл бұрын

Thank you so much! This was so helpful! I have an exam tomorrow and was really confused before watching this!

@abinandankumar5283 4 жыл бұрын

Why n-1 for sample to calculate Standard deviation?

@peterkacheka4402 5 жыл бұрын

Am asking for the interpretation please

@LSAMace 5 жыл бұрын

if i think this is easy will i do good in statistics class?

@nurlatifahmohdnor8939 2 жыл бұрын

Page 1 - 18 Cathode Ray Tube or The video d.: 1 Monochrome D. U. 720 dots × 348 dots (resolution) 9 × 14 dots (characters in a matrix) 2 Colour Video D.U. What are the 4 different basic colours at one time?

@hlengiwengutha7844 3 жыл бұрын

Help please. A retailer observes that the demand for a popular board game averages 40 per week with the standard deviation of 13. If the seller wishes to have adequate stock 99% of the time, at least how many games must she keep on hand?

@riniannregi6520 5 жыл бұрын

awesome easy way to understand. 😁

@riniannregi6520 5 жыл бұрын

thank you sir

@nayararenteria 4 жыл бұрын

So basically there is two ways to solve it depending on what it’s asking?? If it’s asking for sample you have to subtract n-1 & if it’s asking for population it’s just like 5 for example ??

@NaturelySpace Жыл бұрын

Thank you

@smartman9849 5 жыл бұрын

How we can calculate the percentage of 5 years old could excite in this class?

@amanjasrotia8749 3 жыл бұрын

Please clear me that why was the denominator in terms of age was n-1 where as for population it us N. Is there any more things in which n-1 is used other than N. Please clear my doubt, anyone

@omiseika4104 3 жыл бұрын

Hi sir I would like to ask at 12:49 why 5.4? I calculate here and it shows that 5.29

@ninoelcastro2905 6 жыл бұрын

Dude i laugh at 3:42 gonna say it happens on class Lmao

@lindseyhendrix2405 4 жыл бұрын

real talk 😂 lmao it even frightened me just now because I honestly forgot how to do all this but whenever I took stats in college, I distinctly remember our professor writing out that formula for the first time and the immediate horror on all of our faces. at first glance, that formula had me rethinking my entire life choices 😂😂

@balasiusshikongo2719 4 жыл бұрын

Thank you so much Sir! Your video was so helpful, but my final answer after i put 27.2/4 in a square root, i did not get 2.607..., i got 1.303840481. Maybe you can help me on how did you get that answer! I will appreciate your help.