Question 452798: Given the following frequency distribution, find the mean, variance, and standard deviation. Please show all of your work.
Errors Frequency
56-58 22
59-61 14
62-64 24
65-67 19
68-70 19
Need to understand the step needed to complete this.
Answer by stanbon(75887)   (Show Source):
You can put this solution on YOUR website! Given the following frequency distribution, find the mean, variance, and standard deviation. Please show all of your work.
Errors Frequency
56-58 22
59-61 14
62-64 24
65-67 19
68-70 19
Need to understand the step needed to complete this.
-------
You need the class average for each class; called the class mark.
1st class: (58+56)/2 = 57
2nd class: 60
3rd class: 63
4th class: 66
tth class: 69
--------
Multiply each by the frequency for the class
22*57
14*60
24*63
19*66
19*69
----
Add all those products.
Divide by the sum of the frequencies to get the mean.
----
etc.
=====================
Cheers,
Stan H.
=====================
|
|
|
