Please help me figure them out.
1. In the 105th Congress, the Senate consist of 55 Republicans and 45 Democrats. If a committee is formed by randomly selecting four different senators, what is the probability that they're all Republicans?
2. It's common for public opion polls to have a confidence level of 95% meaning that there is .95 probability that the poll results are accurate within margin of error. If five different organizations conduct independent polls, whats the probability that all five of them are accurate within the claimed margins of error?
3. Determine if property distributions is givin. If not, identify requirements not satisfied. If it is, find mean and standard deviation.
In a study of brand recognition of Sony, groups of four consumers are interviewd. If x is the number in the group who recognize the Sony brand name, then x can be 0, 1, 2, 3, or 4 and the corresponding probabilities are 0.0016, 0.0250, 0.1432, 0.3892, and 0.4096.
4. Ten percent of American adults are left handed. A statistics class has 25 students in attendance.
a. find the mean and standard deviation for the number of left handed students in such classes of 25 studnets.
b. would it be unusual to survey a class of 25 stduents and find 5 of them are lefthanded. why?
1) (55/100)*(54/99)*(53/98)*(52/97)
2) .95^5
3) The sum of the probabilities should add to 1
4) mean of binomial is n*p, standard deviation is sqrt(n*p*(1-p)). Take it from here.
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