Ok I've got a maths exam on monday and one of the things that is going to be inside it is standard deviation.(adsbygoogle = window.adsbygoogle || []).push({});

Problem is I don't get it one bit. I tried googling it but I didn't understand any of it.

Could someone explain to me how I would find the estimated standard deviation for the following data please?

Profits (1000s)--------Frequency

-10<x<10------------2

0<x<10---------------5

10<x<20-------------12

20<x<30-------------20

30<50-------------61

The formula is

Square root off (Total (x-mean of x) squared divided by n but I dont get what x and n are.

The estimated mean is 31350

Please help

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# Standard Deviation Please help

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