Question

The length of a text messaging conversation is normally distributed with a mean of 2 minutes and a standard deviation of .5 minutes. What is the probability that a conversation lasts longer than 3 minutes?

Answer 1

Let
`x` be a random variable which represents the length of a text messaging conversation
`\Rightarrow`
`P(x\ \textgreater \ 3)=1-P(x\ \textless \ 3)=1-P(z\ \textless \ (3-2)/(0.5))=1-P(z\ \textless \ 2)=`
`1-0.97725=0.02275`.