Percentiles - Introductory Statistics
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- Опубликовано: 9 сен 2024
- This video covers the meaning of percentiles in introductory statistics. A percentile score indicates the percentage of values below a certain point.
Percentiles
Quartiles
Deciles
Median
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Video Transcript:
In this video we'll take a look at percentiles. Percentiles indicate the location of a score in a distribution and percentiles range from 1 to 99. Let's go ahead and take a look at an example. So suppose that John scored at the 59th percentile on an exam. If John scored at the 59th percentile this means that he scored better than approximately fifty-nine percent of the people on the exam. As a second example suppose that Margarita scored at the 85th percentile on a standardized test such as the SAT. As she scored the 85th percentile this indicates that Margarita scored better than 85% of the people on the exam. So percentiles indicate the percentage of scores that a given value is higher or greater than. So for example a person who scored at the 3rd percentile they scored better than three percent of the examinees and a person who scored at the 40th percentile scored better than forty percent of the examinees. Percentiles can also be thought of as dividing scores into two separate groups. So for our example with the 3rd percentile, that indicates once again that 3% scored below that point and if 3% score below that point, then everyone else, or the remaining 97% scored above that point. And for the 40th percentile that indicates once again that 40% of the people scored below that point which means that the remaining 60% of people scored above that point. So percentiles really divide the distribution into two separate parts. Certain percentiles go by other names as well which you should be aware of. For example, the 25th percentile that indicates once again that the person who scored the 25th percentile they scored better than 25% of the examinees. Now that exact percentile is also known as Q1 or the first quartile. The 50th percentile indicates that the person who scored there, scored better than 50% of the examinees. Now the 50th percentile is known as Q2 or the second quartile. And the 50th percentile or Q2 is also equal to the median as it splits the distribution exactly in half. So if someone reports the 50th percentile or if they report the second quartile those two are the same thing and that's also equal to the median. The 75th percentile indicates that the person who scored there did better than 75% of the examinees and this is known as Q3 or the third quartile. So in summary, Q1 is the 25th percentile also known as the first quartile, Q2 is the 50th percentile and known as the second quartile and this is also equal to the median and then finally Q3 or the 3rd quartile is equal to the 75th percentile. Finally there are also deciles which are described in many statistics textbooks. And D1 is the first decile. Now the first decile's equal to the 10th percentile. The second decile is known by D2 and it's equal to the 20th percentile. D3 is the third decile or the 30th percentile and so on until we get to D9 which is the ninth decile or the 90th percentile. So the first decile or the 10th percentile this separates the bottom 10% of examinees from the top 90%. The second decile separates the bottom 20% from the top 80% and so on. The smallest percentile is the first percentile and separates the bottom 1% of scores from the top 99%. And the largest percentile is the 99th percentile and the 99th percentile separates the top 1% of the scores from the bottom 99%. Now recall that the 99th percentile would indicate that 99% of the people scored below that point. So that's why it separates the top 1% from the bottom 99%. And as a note it's important to know that there are no such things as the zero or one hundred percentiles. So as I said at the beginning of this presentation percentiles range from 1 to 99. And one other note, percentiles often cause confusion to people who might receive like their son or their daughter's scores on a standardized test in school. So on a score report a person will get a raw score and then they'll get a percentile and it'll say something like 65 and when they see the 65 many people mistakenly think that that means that their son or daughter scored a 65% on the test but that's just a percentile. So it indicates that they scored better than 65% of their peers on the exam so indicates they did pretty well and it has nothing to do with the percentage of questions that they answered correctly. So on those score reports those are percentiles that are reported and it says that typically it has a column labeled percentile or something to that effect and it will report the exact percentile.
some people might be good at math and think your video is long. For me, it made my life easier. thank You.
AMEN!!!!!!!!
🌟🌟🌟
After years of researches, I eventually found the one who has explained me clearly what percentile means. I mean by that,that I eventually understood that notion. Thanks a lot.
Many thanks! I watched it by chance but your teaching style is so simple and easy to understand.
Man I THINK YOU SAVED MY GRADUATION DAY ..!!
I found this video to be VERY helpful and clear! Thank you!
Thanks you made my day!
I was struggling to understand my undergrad lecture on percentile but you made it easy :D
OMG, was that easy! thank you for breaking it down.
Sir, very reliable video and life saving clear explanation.
very helpful to understand percentile in a very simple way. Thank you
Thanks a lot for clearing out my doubts regarding these topics , was lucky to find this really informative video. Thank you for sharing
So useful video with detailed examples! It must be liked
This was supposed to be taught to me all the way back in 6th grade, but at that moment in time they were teaching using mostly I-Ready, and unfortunately I learned pretty much nothing from it, so now I've just decided to look this up because I remembered that I have no clue what percentiles are and this completely cleared it up for me
I'm so glad they ditched I-Ready almost completely by the end of 8th if I remember correctly
ty for the explanation, was easier for me then reading the explanation for some reason.
This helped a lot, thanks!
Thank you. This helped a lot ♥️
this made my life so much easier
very informative within a short time, thanks
Really to the point and good!
You just saved my brain from hell LOL! Thank you!!!!!!!!!
This was so helpful. Thank you
best video my brother, this my first time understanding this percentile thing... thank you so much
Clearly explained and understandable. Thanks!
literal and clear thanks
This is awesome ! Thanks !
Thank you
cleared all my doubts..:)
very good at last i understood, percentile is nothing related with the marks in the exam is the position.location in he group GREAT!! M,ANY THANKS
Life saver for students
At 4:45, he sums up everything at this point.
Great Video.. Easy And Simple
Thank you a lot!
Thank you so much for this clear explanation!
great explaination! Thanks
Thank you so much
the percentile at which I usually score is referred to as the imbe-cile
Very helpful explanation, thank you
I'm pretty sure you said the same thing for 6 min.
some people need that
@@cacattack67 what must be added to the polynomial x^3-4x^2+x+2 to make it x^2-x+4?
That drills a concept into the head, William, which is much needed.
@@nabarajbaral2063 -x^3+5x^2-2x+2
Very informative thank you 🌸
One advice: maybe put a bit more enthusiasm into your voice. It makes very sleepy to listen to you. Except for this, thumbs up.
Thanks a lot, your video has helped me out. Bigop
Really great explanation! You've cleared all my doubts. Thank you so much :)
Thank you :)
thanks alot bro
Wow THanks
Thx this video was very helpful for me. It helped me understand percentile and got a high grade :)
Very glad to hear - thanks for sharing!!!
Amazing 🌸🌸
Thank you 😌
I liked your video.
2:30 - 50th percentile splits the distribution exactly in half.
Very nice!
Good explanation 10/10
So a percentile, from what to what number does it go? Because you can't have overlap right?
Does that mean the 2nd percentile goes from 1,01 to 2,00 or 1,00 to 1,99?
Hi, your video is good..Can I use this one for my multi-media studies?
You bet. Glad to hear it helped!
His voice sounds very much like the guy in Purple Math, now that I think about it!!
3rd OK i get it, 40th Ok i get it...but what about the rest...i am very dumb. Please repeat for all 1 to 99 in a table. ;)
hey dude thank you so much
Superb!
u save my life
what if a person scored the highest in the class , then what percentile would it be as there is no better scorer than that person
YES! That means I did extremely good on my test! (99th percentile)
Not necessarily. For example, if 100% of the people taking the test scored below 10% of the maximum score, then the 99th percentile would still mean a score below 10% of the maximum, and you did extremely well among your peers, but extremely poorly in terms of correct answers given. I'm sure that's not the case in your specific example, but it's something to keep in mind. Congrats on your test, albeit a year later.
Then what does it mean if it says upper 10 percentile
Peace & love 💕
My doubt was cleared thanku
I'm living for his monotone voice
but why are we not considering other 5% when we are considering 95th percentile.
If few people get full marks, what will be the percentile of the people getting full marks!?
god bless you
So you didn't even help solve anything. Just defined words. -_____-
how many from jee result ?
I am now 99 percentile sure that you just confused me even more. Whattttttt just happened!? NEXXXTTTT.
I have homework on child birth percentiles and I have absolutely no idea how to do it I’m just really wishing something would help rn😭
life is better if u play this video at 1.5 speed
The daughter might have a 65th percentile score but scored below 65% in the examination. In that case, she wouldn't mind if her parents mistook the percentile for her score.
can you have decimal percentiles, like 1.5th percentile or 56.3th percentiles or are there only whole percentiles?
How about exceedence percentile? what is that? and how to calculate it?
u sound like ross geller
are you sure it's accurate to say that 97% of a group scored above the third percentile and 3% scored below? Let's say 100 people did an exam, and ten of those people scored "X". Let's also say that out of the remaining 90 people, half of them scored better than "X" and half scored worse than "X". That means that only 45% of people scored above the people who scored "X", and 45% below. Your description doesn't seem to take into account the percentage of identical values within a group.
for small data u can use histogram or SD, Percentile works with a large number of objects, big data
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Play the video at 1.25× speed...you'll thank me later
I think the explanation is imprecise and could be misleading or confusing for the learner and bring him to error.
1) it should use the term "higher" not "better" because higher numbers is not always better numbers.
2)the 1st percentile and the 99th percentile are not the smallest and largest percentile respectively, because they are actually of the same size: they both include 1% of the data. But again they can be called lowest and highest, or percentile with the lowest/smallest value and percentile with the highest/largest value.
+Marco Scataglini
Hi Marco,
Thank you for your feedback. I don't disagree with your point in #1. However, if we are talking about test scores, for example, better is appropriate, since higher scores do indicate better performance (on percentage correct scales).
On #2, again, If we are talking about test scores, the 99th percentile is the highest, as there is no such as as a 100th percentile. People often get confused about location of percentiles, and by calling it highest and lowest (in the appropriate context) it immediate communicates information about their location in the distribution. Sometimes this can be more useful than always striving for the most general, universal case.
why do some websites suggest that I should use n+1 in the formula. This confusing because I don't know what I should use.
n=P/100(N) or the other formula n=P/100 (N+1)
Can any of you help me please?
Why do you say that the percentile can't be 100 if you check wikipedia Percentiles it says:
The Nearest Rank method
One definition of percentile, often given in texts, is that the P-th percentile (0
wala, bobo talaga ako.
Thank you
thank you :)
thank you so much