Estimating median, quartiles, percentiles from a grouped frequency table : ExamSolutions

Median, quartiles, percentiles from a grouped frequency table. Estimating values for the median and quartiles for grouped data than ungrouped data.

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[MrGhostBoy]

Video came out 8 years ago and still the best video on YouTube

[sunmeetkhurana]

I was panicking for 12 minutes ago because my S1 mock is tomorrow and I had no clue about interpolation, but thanks to you I have understood it!! Thank you so much!!

[ExamSolutions_Maths]

The median would be in the (20+1)/2 position if the data were discrete. In other words the 10.5th value which will then be the mean of the 10th and 11th values.

[AsiansCrazy]

you are an absolute legend...stay blessed...god bless you sir!

[prodxtendo]

The plain old method that teachers teach aren't any good without proper understanding of it. Thank you for what you do.

[ExamSolutions_Maths]

Pleased to know you have now got it. Well done.

[muneungBeing]

This channel is always helped my mathematics works :)

[ExamSolutions_Maths]

@Peacock2613 Do you realise that these are free videos done in my own time and you want to complain. Shame on you.

[ExamSolutions_Maths]

Because the class limits and class boundaries for this example are the same. If it were 10-19, 20-24, I would use 9.5 - 19.5 etc.

[gaz]

Thank you so much for uploading this video. Excellent and so easily explained... 👏

[willsaldana]

Your a legend thanks so much for your videos helped me so much

[ExamSolutions_Maths]

@MassiusClay7 No probs. Thanks for your support.

[noonecares]

i love your vidoes becuase you explain every step you'r going through unlike other people skip it through

[Yoooomanwhatsup]

the YouTube algorithm is really shit. Have to work hard to get a golden video like this.

[AndrewJames]

Hi,
Do we only use interpolation when estimating means and quartiles in grouped frequency tables?
If the question asks to find the mean and quartiles as in videos 2 & 4 in S1 do we simply use (n+1/2)?
Thanks

[cjhook]

In your previous video on Cumulative Frequency Curves, you stated that for example 165-175 mean't 165< h ≤ 175 but here you're saying in your example 10-20 means "we have four values which are greater or equal to ten but less than 20" which looks like this,
10 ≤ f < 20. Why has the ≤ sign swapped around?

[piedpiper]

wow you made it so easy to understand! Thanks

[ExamSolutions_Maths]

@naruto2710 10- would mean greater than or equal to 10 but less than 20. So the mid point would be taken as 15

[mindfulawareness]

Love this. Please explain how the 'comparing the intervals equation' works. Why does the lhs equal the rhs?

[dgc]

hi, im finding it very difficult getting my head around and understanding the theory/steps to find out the quartile/percentile (06:10 - 07:45), could you please share the formula used that explains what figures i should be using in that calculation please
i just cant seem to understand the formula you are using? is there a layman's formula i can refer to? thank you