Question

9) Identify the name of the distribution that would best serve as a model for each of the following
random variables. Choose one of the following: Binomial, Geometric, Poisson, Hypergeometric, Discrete
Uniform, Continuous Uniform, and Normal.
a) X = the number of yawns that occur in a 50-minute Applied Stats class.
Distribution:_______________________________
b) X = the actual weight of a quarter-pounder before cooking
Distribution:_______________________________
c) X = out of 24 rolls of on ordinary die, the number of times it comes up with six spots showing.
Distribution:_______________________________
d) X = the number of true-false questions a person who is completely guessing gets wrong prior to
finally getting one correct.
Distribution:_______________________________

Answer 1

(a) Since yawning is a more or less rare event the distribution should be Poisson.

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(b) The pre-cooked weight of a quarter pounder should be normal centered around the original weight by considering the fact that this random variable is continuous and should be symmetrically distributed around its mean and is concentrated around its mean.

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(c) This distribution is clearly binomial.

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(d) SInce this random variable measures the trials needed to get the first success, it must be geometric .