Question

The length of a social media interaction is normally distributed with a mean of 3 minutes and a standard deviation of 0.4 minutes.
What is the probability that an interaction lasts longer than 4 minutes?


1)0.0045254
2)0.043351
3)0.0095254
4)0.006209

Answer 1

Answer:   4) 0.0062097

Step-by-step explanation:

Given : The length of a social media interaction is normally distributed with a mean of $\mu=3$ minutes and a standard deviation of $\sigma=0$ minutes.

Using the formula , $z=\dfrac{x-\mu}{\sigma}$, the z-value corresponding to x=4 will be :-

$z=\dfrac{4-3}{0.4}=2.5$

Using the standard normal distribution table for z-value , the  probability that an interaction lasts longer than 4 minutes will be :-

$P(z>2.5)=1-P(z\leq2.5)=1-0.9937903=0.0062097$

Hence, the probability that an interaction lasts longer than 4 minutes = 0.0062097

Answer 2

Your answer is the last one.