Question 227163: You are given the following frequency distribution for the number of errors that students made in a test
Errors..... Frequency
0-2..... 11
3-5..... 9
6-8..... 7
9-11..... 7
12-14..... 13
Find the mean, variance, and standard deviation.
Please figure this problem out. It is so confusing. Thanks
Answer by stanbon(75887)   (Show Source):
You can put this solution on YOUR website! You are given the following frequency distribution for the number of errors that students made in a test
Errors..... Frequency
0-2..... 11
3-5..... 9
6-8..... 7
9-11..... 7
12-14..... 13
Find the mean, variance, and standard deviation.
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Use the class mark as the representative value for each class.
Multiply each class mark by the frequency of the class; then add the products.
Divide the sum (above) by the sum of the frequencies to get the mean.
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I used a TI calculator to get:
mean = 7.1277
variance = 21.43
stand deviation = sqrt(variance) = 4.6293
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Cheers,
Stan H.
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