Question

For the following random variables, would the distribution best be described as geometric, binomial, Poisson, exponential, uniform, or normal?

a) The number of goals that a team scores in a hockey game.

b) The time of day that the next major earthquake occurs in Southern California.

c) The number of minutes before a store manager gets her next phone call.

d) The number of 3's that appear in 20 rolls of a die.

e) The number of days out of the next 10 that a stock will go up.

f) The amount of time before the next customer arrives in a store.

g) The number of particles that a radioactive substance emits in the next two seconds.

h) The number of free throws that a basketball player needs to make before missing one.

Answer 1

(a) Poisson as number of goals has wide range of values which it can take and be anything. (b) uniform exponential as it can enter at any time over a time scale. (c) uniform as coming of all uniformly distributed. (d) binomial as trial and probability associated with each trail is fixed. (e) binomial as trial and probability associated with each trail is fixed. (f) uniform as coming of customer is uniformly distributed. (g) Exponential as probability distribution vary with time. (h) Geometric, as trail will continue until objective met.