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# Frequency tables

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1.
x Freq Probability P(x) xP(x) (x-µ )sqP(x)
9 3604
10 3131
11 2749
12 2488

Total µ= sigma sq=

Determine the probability distribution of the randum varible x.
What is the probability taht a randomly selected student is either in the 9th or 10th grade?
What is the probability that a randomly selected student is in at most 11th grade?
Find the mean and standard deviation of the random variable x.

https://brainmass.com/statistics/frequency-distribution/frequency-tables-22973

#### Solution Preview

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<br>Determine the probability distribution of the random varible x.
<br>
<br>Total number of students = 11972
<br>P(x=9 ) = 3604/11972 = 0.30
<br>
<br>P(x=10) = 3131/11972 = 0.26
<br>
<br>P(x=11) = 2749/11972 = ...

#### Solution Summary

x Freq Probability P(x) xP(x) (x-µ )sqP(x)
9 3604
10 3131
11 2749
12 2488

Total µ= sigma sq=

Determine the probability distribution of the randum varible x.
What is the probability taht a randomly selected student is either in the 9th or 10th grade?
What is the probability that a randomly selected student is in at most 11th grade?
Find the mean and standard deviation of the random variable x.

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