Question

What is probability that two randomly selected people are born on the same weekdays?

Using Ti-34 calculator

Equations/answer written out using

binomcdf(x,x,x)

Binompdf(x,x,x)

Invnorm

InvT

tcdf

If possible/needed to solve the equation

Answer 1

Note- This is a problem of basic probability. Any standard distribution is not at all required to solve this problem.

There are 7 days in a week. Day of birth of a person is independent of day of birth of other persons.

Number of possible combination of weekdays as birth day of two randomly selected people is $\tiny 7*7=49$

Number of possible ways so that two people were born on the same day is $\tiny 7$

Required probability is given by

$\tiny \frac {7}{49}=0.1428571$