Past records show that at a given college 20% of the students who began as psychology majors either changed their major or dropped out the school. an incoming class has 110 beginning psychology majors. what is the probability that as many as 30 of these students leave the psychology program?

An incoming class has 110 beginning psychology majors. According the record 20% of them will either change their major or will drop out of the school. 20% of 110 is:
20/100 *110=22
So, 22 students will change their major or will drop out of the school.
The probability that as many as 30 of 110 students leave the psychology program is zero . 22 < 30 which means that the number of the students who will leave the psychology program will always be smaller than 30. 

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