Question 259277: please help!!!!!!!!!!!!!
frequency distribution for the number of errors that teacher made in a quiz
errors frequency
0 - 2 14
3 - 5 1
6 - 8 9
9 - 11 19
12 - 14 17
find the mean, variance, and standard deviation.
thank inadvance
Answer by stanbon(75887)   (Show Source):
You can put this solution on YOUR website! frequency distribution for the number of errors that teacher made in a quiz
errors frequency
0 - 2 14
3 - 5 1
6 - 8 9
9 - 11 19
12 - 14 17
find the mean, variance, and standard deviation.
--------------------
Since the data has been put into intervals you have
lost the true data values.
So you use the class mark for each class as representative of the data
values that fell into that class.
---
You frequency distribution becomes:
Mark::freq
1----14
4----1
7----9
13---17
-----------------
Now you find the mean , variance, std for that set of data:
mean = 6.9512..
std = 4.8423
variance = std^2 = 23.45
============================
Cheers,
Stan H.
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