Residents of the Shire, being generally distrustful of wizards, give Gandalf an approval rating of 28%

Question

Find the probability that fewer than 19 residents of the Shire, taken out of a random sample of 112, approve of Gandalf.

Answer 1

Hi Madison,

This is like your Hitchhiker’s Guide problem, but with one key difference. We are interested in fewer than, not at most. It’s still a binomial distribution, so you can still use binomcdf, but we have to change n:

n = 112

p = 0.28

x = 18 (This is important. We need to subtract 1 from 19 since question asked specifically for fewer than.)

2nd-VARS-binomcdf(112, 0.28, 18) = 0.002

I hope this helps.