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# probability

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The probability that a college student uses Twitter for social networking is 0.92 if 9 students are chosen at random use the binomial probability formula to find the probability that more than 7 use Twitter

Feb 16, 2020

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Thanks for the A2A.

First, let's convert .92 into a fraction.

That would be 92/100. Now let's figure out the probability of 1 case of 1 number(there are 2 numbers, 8 and 9).

To have exactly 8 students, that would be $$\frac{92^8*8}{{100}^{9}}$$ probability for 1 case. Compute that and you'll get .041.

To find the total number of cases in #8,  ​we can use the combination formula to get $$\frac{9!}{8!}$$ which is simplified to 9.

.041 multiplied by 9 is approximately .37.

Now we can figure out the probability for exactly 9 students.

It is .472. There is only one way we can sort 9 students from 9, so we keep it.

.37+.472  is approximately 84.17%.

Cheers!

Feb 17, 2020