Variance and Standard Deviation: Sample and Population Practice Statistics Problems

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  • Опубликовано: 4 ноя 2024

Комментарии • 255

  • @Dee-ye2dk
    @Dee-ye2dk 5 лет назад +46

    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 RUclips. Thank you for this video, currently taking stats in college.

  • @sayedalihaider7307
    @sayedalihaider7307 2 года назад +10

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

  • @fernandomaron3498
    @fernandomaron3498 6 лет назад +287

    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
      @caseymaps4918 6 лет назад +1

      That's so true

    • @jasontutorials4809
      @jasontutorials4809 6 лет назад +6

      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
      @stephenkiama4665 6 лет назад +1

      I agree with you

    • @KK-yt8qw
      @KK-yt8qw 5 лет назад +1

      Stephen Kiama e

    • @sirhilmohamed1193
      @sirhilmohamed1193 5 лет назад +1

      I seconded you.

  • @munequa81
    @munequa81 15 дней назад

    My God THANK YOU SO MUCH!! I'm taking Statistical Analysis as a required course 4 hours a week and you broke down this formula in a clear and simple way, that I feel confident in taking my midterm. Thanks again!

  • @hlalelemohale7296
    @hlalelemohale7296 4 года назад +6

    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!!

  • @angelicaibanez5327
    @angelicaibanez5327 4 года назад +1

    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!!!

  • @exploringim6191
    @exploringim6191 4 года назад +2

    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!

  • @AndrewMcNeillMusic
    @AndrewMcNeillMusic 6 лет назад +18

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

  • @elesahefner9155
    @elesahefner9155 4 года назад +2

    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!!!

  • @GrimFemme
    @GrimFemme 7 лет назад +59

    You just saved my grade. Thank you.

  • @dennisecallejas7185
    @dennisecallejas7185 7 лет назад +2

    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 !

  • @hanesmitter1469
    @hanesmitter1469 5 лет назад +8

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

  • @elirivera8880
    @elirivera8880 3 года назад

    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!

  • @enteryunion1673
    @enteryunion1673 4 года назад

    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. .

  • @nosiphosimelane5736
    @nosiphosimelane5736 2 года назад

    I really needed this lesson before my STAs exam

  • @nurulainnajwasuhaimai4418
    @nurulainnajwasuhaimai4418 3 года назад

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

  • @linetgachiuki3078
    @linetgachiuki3078 5 лет назад +6

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

    • @statisticstuber6110
      @statisticstuber6110 3 года назад

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

  • @gedeonkibambe9930
    @gedeonkibambe9930 4 месяца назад

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

  • @NaturelySpace
    @NaturelySpace 2 года назад +1

    Thank you

  • @Elviskiol-do7dy
    @Elviskiol-do7dy 4 месяца назад

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

  • @koba3174
    @koba3174 Год назад +1

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

  • @af5104
    @af5104 2 года назад

    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.

  • @tamaraseid7413
    @tamaraseid7413 6 лет назад +2

    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.

  • @mbangetaheteng3419
    @mbangetaheteng3419 5 лет назад

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

  • @joyceguevara8302
    @joyceguevara8302 5 лет назад

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

  • @Name_idkk
    @Name_idkk 3 года назад

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

  • @DuolNguotGatdoar
    @DuolNguotGatdoar Год назад

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

  • @selynamcgowan9110
    @selynamcgowan9110 5 лет назад

    Help: 4. Bone density can be measured using a DEXA test. Bone density for a 25-year-old woman is normally-distributed with a mean of 956 g/cm2 and a standard deviation of 5.52 g/cm2. Let X be the bone density of a randomly selected 25-year-old woman in g/cm2.

  • @analync.torres625
    @analync.torres625 3 года назад +1

    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☺️🙏🏻

  • @nurlatifahmohdnor8939
    @nurlatifahmohdnor8939 2 года назад

    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?

  • @lovemendez5406
    @lovemendez5406 5 лет назад +4

    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
      @abubakaryunusa2604 4 года назад

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

  • @afiacodlin3739
    @afiacodlin3739 Год назад

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

  • @eugenejoseph6666
    @eugenejoseph6666 5 лет назад +1

    2.3 * 2.3 = 5.29 , round off will be 5.30 , where did you get 5.4 from ?

  • @MathsclassKI
    @MathsclassKI 5 лет назад +1

    very clear
    good teaching

  • @fabishkenya9263
    @fabishkenya9263 3 года назад

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

  • @nayararenteria
    @nayararenteria 5 лет назад

    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 ??

  • @NoNamae0_0
    @NoNamae0_0 2 года назад

    bro ur a lifesaver.

  • @lekpjedits18
    @lekpjedits18 5 лет назад +1

    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

  • @yogeshpareek181
    @yogeshpareek181 4 года назад +1

    Realy great vedio sir thax for helping

  • @smileyshine1163
    @smileyshine1163 5 месяцев назад

    Super explanation
    Thank you sir

  • @mindy8331
    @mindy8331 2 года назад

    Thank you for this video. Very helpful.

  • @tarikuamante4546
    @tarikuamante4546 4 года назад

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

  • @charlottewaller6269
    @charlottewaller6269 5 лет назад

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

  • @lailauthman5454
    @lailauthman5454 5 лет назад +2

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

  • @LSAMace
    @LSAMace 5 лет назад +1

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

  • @odogwuhenry
    @odogwuhenry 2 года назад

    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

  • @analync.torres625
    @analync.torres625 3 года назад

    Where did you get the 6.8yrs because the square root of 2.607 is not the same.

  • @monroemullinix5974
    @monroemullinix5974 2 года назад +1

    Please stop suggesting that students use a calculator to do basic arithmetic like 4+6+8+4+10. I am working with a ten-year-old South Korean student and he could probably teach an American AP Statistics class.

  • @Domestikos88
    @Domestikos88 4 года назад +1

    I don't understand how 2.6 is 27.2/4 squared.

  • @ahamedakmal7104
    @ahamedakmal7104 7 лет назад +2

    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?

  • @hlengiwengutha7844
    @hlengiwengutha7844 3 года назад

    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?

  • @tammymcfee9325
    @tammymcfee9325 5 лет назад +1

    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
      @kkurachannel2715 5 лет назад

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

  • @----cp6xy
    @----cp6xy Год назад

    This video was so helpful 🙌

  • @mrhq3153
    @mrhq3153 5 лет назад

    Good explaination.

  • @amanjasrotia8749
    @amanjasrotia8749 3 года назад

    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

  • @danizooo2129
    @danizooo2129 4 года назад

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

  • @minivantoirog2089
    @minivantoirog2089 4 года назад +1

    Hey the formula is different than the one on the internet without negative 1

  • @abinandankumar5283
    @abinandankumar5283 4 года назад

    Why n-1 for sample to calculate Standard deviation?

  • @prateeksrivastava64
    @prateeksrivastava64 3 года назад

    I have a query. why sample std. deviation and population std. deviation formula are differ ? please clear me .

  • @Jay-g4b4g
    @Jay-g4b4g 2 месяца назад

    Where did the minus 1 come from? At 3:38 and at 7:06.

  • @ajayjackson7727
    @ajayjackson7727 4 года назад

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

  • @balasiusshikongo2719
    @balasiusshikongo2719 4 года назад

    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.

  • @dasbodh5799
    @dasbodh5799 4 года назад

    Nice explanation 👍👍

  • @lifewithcharity8573
    @lifewithcharity8573 7 лет назад +23

    I think I just became a stastician

  • @winennwetwipes4462
    @winennwetwipes4462 6 лет назад +15

    is this tony stark?

  • @louiscayohwe
    @louiscayohwe 6 лет назад

    I LOVE YOUR WORK SIR

  • @Masteridea101
    @Masteridea101 5 лет назад

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

  • @naumanshabbirawan4232
    @naumanshabbirawan4232 5 лет назад

    thank you so much dear sir

  • @n.g.6442
    @n.g.6442 4 года назад

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

  • @tavuzzi6955
    @tavuzzi6955 6 лет назад

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

  • @elividal7202
    @elividal7202 6 лет назад +1

    super clear explanation

  • @nazmulislam3580
    @nazmulislam3580 5 лет назад

    i like your classes
    very much

  • @nakasisara4400
    @nakasisara4400 6 лет назад +2

    I just like this class

  • @MrOusmane23
    @MrOusmane23 Год назад

    he is just amazing

  • @Masteridea101
    @Masteridea101 5 лет назад

    can someone explain the fundamental behind
    1) how this figure 2.6 is related to the initial series of 5 numbers?
    2) how this 5.4 is related to the same initial series?
    what is the usage of these two figures?

  • @sherigeorge5874
    @sherigeorge5874 4 года назад

    so when do we use N as a denominater, and when N-1??

    • @hlalelemohale7296
      @hlalelemohale7296 4 года назад

      N=all data points(all population) given
      N-1= sample of all data points given.

  • @omiseika4104
    @omiseika4104 3 года назад

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

  • @amancabdi3035
    @amancabdi3035 5 лет назад

    we need more

  • @MikhaelAhava
    @MikhaelAhava 5 лет назад

    I think this will help me thanks.

  • @taranaali6025
    @taranaali6025 5 лет назад

    Good explanation

  • @vhype233
    @vhype233 2 года назад

    Can you explain the root that 27.2/4 🤔

  • @farrahkhan2160
    @farrahkhan2160 6 лет назад

    Nice easy to understand

  • @sunkarimourya5739
    @sunkarimourya5739 5 лет назад

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

  • @smartman9849
    @smartman9849 6 лет назад

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

  • @alejandrabradley8180
    @alejandrabradley8180 6 лет назад +1

    Thank you for the help, great example!!

  • @jimvenniceatienda816
    @jimvenniceatienda816 6 лет назад

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

  • @riniannregi6520
    @riniannregi6520 5 лет назад

    awesome easy way to understand. 😁

  • @michaelbarrionbalaoro5896
    @michaelbarrionbalaoro5896 3 года назад

    How did you get 2.607?

  • @osenisuliat5041
    @osenisuliat5041 4 года назад

    Thanks so much, really helpful

  • @mklibuto2879
    @mklibuto2879 7 лет назад +1

    OKAY, GET IT NOW!

  • @0069yj
    @0069yj 5 лет назад

    Great work ... thank you

  • @maheshwaripanuganti5889
    @maheshwaripanuganti5889 3 года назад

    Thank you so much

  • @solomontibebu7248
    @solomontibebu7248 5 лет назад

    best example

  • @monyroath
    @monyroath 4 года назад

    Having a final today so here I am

  • @fatimkakia5419
    @fatimkakia5419 2 года назад

    Please how did u get this 27,2

  • @wynceldupal-ag3347
    @wynceldupal-ag3347 5 лет назад

    Wherr do u get 5.76? I dont understand that portion

  • @melissarocha1516
    @melissarocha1516 8 лет назад +17

    why is it n-1

    • @darwinyip9481
      @darwinyip9481 8 лет назад

      Melissa Rocha I have the same question

    • @mitchellwu22
      @mitchellwu22 7 лет назад

      now the reason why it is N-1 it is because the first problem he is dealing with only the sample, the equation used is N-1 at the bottom where as a population where if someone sampled everyone then it is divided by N only. In terms of why is sample N-1 that's just something the statisticians have used many years ago.

    • @korrinjohnson8992
      @korrinjohnson8992 7 лет назад +5

      I don't understand this explanation

    • @veiakas
      @veiakas 7 лет назад +10

      If you had the whole population of values, e.g. every single child in the world ("POPULATION"), then you would use N. Since we cannot realistically use the data from every single child in the world, we use a small SAMPLE from that population. It is basically a conventional agreement that since we use a SAMPLE as opposed to the whole POPULATION, then we will introduce an error. Thus N-1.

    • @AsgharKhan-bv2hc
      @AsgharKhan-bv2hc 7 лет назад +1

      n_1 is for sample and just n is for population

  • @leonardomartin4063
    @leonardomartin4063 4 года назад

    How did u get 2.607? In standard deviation?

  • @estherwanjiru6001
    @estherwanjiru6001 4 года назад

    Thank you sir

  • @vannessavillarante3333
    @vannessavillarante3333 6 лет назад +2

    Where did you get the 2.6?
    Plss reply.

    • @m1glr4mrz
      @m1glr4mrz 6 лет назад +2

      27.2÷4=6.8
      Then Square Root of 6.8
      =2.607....