Statistics: Using the Binomial distribution,

Question

Using the Binomial distribution,

If n=8 and p=0.8, find P(r=7)

Answer 1

No one calculates this by hand anymore. We all use calculators or software.

For a single discrete event (ie r = 5 or 7 or 8) we use the probability density function , not the cdf.

Examples for n = 10, p = .5, r = 3)

Ti-8x : bipdf(n,P(x),r) or bipdf(10,.5,3) = 0.1171875

Excel : BINOM.DIST(number_s,trials,probability_s,cumulative) or BINOM.DIST(3,10,.5,FALSE) = 0.1171875

R : dbinom(x, size, prob) or dbinom(3,10,.5) = 0.1171875

From this you should be able to do your homework question.

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