# GRE quiz (interquartile range (IQR)) problem

**URL:** <https://talk.achievable.me/t/gre-quiz-interquartile-range-iqr-problem/1529>\
**Category:** GRE\
**Created:** [May 6, 2022, 5:42pm UTC](https://talk.achievable.me/t/gre-quiz-interquartile-range-iqr-problem/1529 "2022-05-06T17:42:42Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![Polancas](https://talk.achievable.me/letter_avatar/polancas/32/6_22734026db12803ebb3e059622ac3534.png) [@Polancas](https://talk.achievable.me/u/Polancas)\
**Post date:** [May 6, 2022, 5:42pm UTC](https://talk.achievable.me/t/gre-quiz-interquartile-range-iqr-problem/1529/1 "2022-05-06T17:42:42Z")

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![image](https://d2a8kmyc1dvkyq.cloudfront.net/original/1X/cb3cf918a9a41e629f94d3f3936bc0ca63921ae6.jpeg)

I’m confused how Q1 median is 11

How I solved my part for Q1 median:  
For interquartile range (IQR) part…  
Q1 med(8,9,11,16,16) = 60 then divided by 5 = 12

Did I do math wrong? If so, can someone help me clarify it? Please?

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**Author:** ![Justin](https://talk.achievable.me/user_avatar/talk.achievable.me/justin/32/41_2.png) [@Justin](https://talk.achievable.me/u/Justin)\
**Post date:** [May 6, 2022, 7:49pm UTC](https://talk.achievable.me/t/gre-quiz-interquartile-range-iqr-problem/1529/2 "2022-05-06T19:49:14Z")

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Hi @Polancas, welcome to Achievable, and thanks for posting!

Your math is _almost_ correct. The difference is that you’re calculating the **mean** , but for IQR you need to calculate the **median**.

**Mean** is the typical “average” we talk about: the sum of the value divided by the number of values. It’s as you did the math: mean = (8 + 9 +11 +16 +16)/5 = 60/5 = 12

**Median** is the middle-most value. Since it’s already sorted, we can just pick the middle one: median = (8,9, **11** ,16,16) = 11.

For **median** , if it is a set with an even amount of numbers, you take the **mean** of the middle-most two values: median = (8, **9** , **16** ,16) = (9+16)/2 = 12.5

Hope this helps! Please let me know if I can explain further or if there are other topics I can clarify.

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**Author:** ![Polancas](https://talk.achievable.me/letter_avatar/polancas/32/6_22734026db12803ebb3e059622ac3534.png) [@Polancas](https://talk.achievable.me/u/Polancas)\
**Post date:** [May 6, 2022, 9:05pm UTC](https://talk.achievable.me/t/gre-quiz-interquartile-range-iqr-problem/1529/3 "2022-05-06T21:05:08Z")

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Oh okay, that makes sense! Thank you!