A few days ago
cshanahan87

Statistics (problem) class average help! Can anyone help?!?

A class has 25 students whose average IQ score is 118. A 26th student is added to the class with an IQ score of 130. What is the average IQ of the class now? How do you solve this problem? STUMPED lol THANKS

Top 5 Answers
A few days ago
shannon3lc

Favorite Answer

Ok well if a class of 25 students has an average score of 118, you know that the sum of their IQs divided by 25 (that is the equation for average: sum of numbers / total number of numbers = average) equals 118, you can find what the sum was. Then you just add in the final number, 130, and this time divide the number by 26 (because you have one more number now). SO….

t / 25 = 118 so t = 118 x 25

and the average = (t + 130) / 26 so…

[(118 x 25) + 130] / 26 = the average.

Good luck

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A few days ago
Merlyn
the mean IQ of the class of 25 is 118 = S / 25 where S is the sum of all the IQ’s of each student in the class.

S = 118 * 25 = 2950

Getting the average of the class with 26 students will be simple.

( S + 130 ) / 26 = 118.4615

This is the sum of the IQ’s of the 25 students plus the IQ of the 26th divided by the new sample size of 26.

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A few days ago
Cat Lover
ok so you times 118 by 25 to get the original total of the IQ scores added together then you would add 130 to that and then divide that number by 26

118 x 25 = 2950

2950 + 130 + 3080

3080 / 26 = 118.461…….

So pretty much it stayed the same. Hope that helped

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A few days ago
Anonymous
We have to use data for 26 people now. So multiply 118 by your original 25 people (2950). Add the 130 (3080) and divide by your total numbers of subjects, which is now 26.

3080 divided by 26 is 118.46.

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4 years ago
?
considering the fact that each familiar deviation is .0.5, your limits are at +2 and -2 SD. look up +2 SD on your danger table to get the % of the curve betwen -2 SD and +2 SD, then multiply this % by utilising 1250.
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