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I need some help please! I am not too sure how to answer question 1.3 regarding the "mid-60& range".

Are they looking for 60th percentile?

Thanks for the assistance!

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  • $\begingroup$ Please add the [self-study] tag & read its wiki. Then tell us what you understand thus far, what you've tried & where you're stuck. We'll provide hints to help you get unstuck. $\endgroup$ – gung - Reinstate Monica Mar 20 '16 at 12:50
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You have to compute the 60% interquantile range, i.e. the range between the 20th percentile and the 80th percentile:

IQR(60%) = 80th percentile - 20th percentile

The interquantile range (IQR) is a measure of statistical dispersion, being equal to the difference between the upper and lower quantiles, in your case the 80th percentile and the 20th percentile (80 - 20 = 60).

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  • $\begingroup$ Thanks Stochazesthai. I am new to stats and would appreciate if you could provide me with a step by step solution in how to work this out. I am not certain how you you derived the 80th and 20th percentile. Please assist! Thanks $\endgroup$ – Mags Mar 20 '16 at 13:15
  • $\begingroup$ You are asked to write the mid-60% range, i.e. the dispersion in the middle 60% of the distribution. To consider the middle 60%, you have to "rule out" the 20% at the extremes of your distribution. Hence, by computing the difference between the 80th percentile and the 20th percentile, you can find the middle 60% range of you distribution. $\endgroup$ – stochazesthai Mar 20 '16 at 13:19
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    $\begingroup$ Thank you so much, that makes alot of sense now! Thanks for the help- i really appreciate it! $\endgroup$ – Mags Mar 20 '16 at 13:20
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    $\begingroup$ The spirit here is right but the letter is wrong, or the ideas are explained awkwardly. The quartiles can only be defined as 25% and 75% quantiles or percentiles. As in the answer, the terms quantile and also percentile are available and totally preferable for values corresponding to other percent points. So the difference concerned could be called an interquantile range, although it is, I suggest, more clearly explained as just a difference between particular percentiles or quantiles. The risk not spotting the difference between interquartile and interquantile is far too high. $\endgroup$ – Nick Cox Mar 20 '16 at 14:59
  • $\begingroup$ Agree. Fixed it. $\endgroup$ – stochazesthai Mar 20 '16 at 16:08

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