(adsbygoogle = window.adsbygoogle || []).push({}); 1. The problem statement, all variables and given/known data

The resistances of 50 resistors are measured and the results recorded are as follows:

Resistance x Frequency

1.) 5 x 17,

2.) 5.5 x 12,

3.) 6 x 10,

4.) 6.5 x 6,

5.) 7 x 5)

Calculate standard deviation of the measurements

2. Relevant equations

3. The attempt at a solution

Added up the frequences and gotn = 50

Multiplied the resistance by its weight or frequency and got the following:

1.) 86

2.) 66

3.) 60

4.) 39

5.) 35

then I added the values up and divided the result by the sum of the frequencies (n) to get the mean (cant do an x bar so I'll denote it as M)

M = 5.7

If I follow the standard deviation formula and add up all results of (x - m)^{2}I get a really low number so if I then divide that really low number by n which is 50 I get something like 0.0049.

What am I doing wrong? Is the x of the formula resistance x frequency in this case since its weighted data Im dealing with?

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# Homework Help: Standard deviation of weighted data

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