Question

Ninja blenders have a 2 year warranty, which means that Ninja guarantees replacement of the blender is it fails within the first 2 years. The blenders last an average of 36 months with a standard deviation of 6 months. What is the probability that Ninja will have to replace your blender if you were to buy one today

a 0.025

b 0.475

c 0.0001

d 0.0235

Answer 1

Answer:

d 0.0235

Step-by-step explanation:

We assume that the lifetime of the blenders follows a normal distribution, with mean of 36 months and standard deviation of 6 months.

We have to calculate the probability that the blenders have a lifetime lower than 24 months, and therefore apply the guarantee.

First, we calculate the z-score:

$z=\dfrac{X-\mu}{\sigma}=\dfrac{24-36}{6}=\dfrac{-12}{6}=-2$

Then, the probability that the blenders lifetime is 24 or less is:

$P(X<24)=P(z<-2)=0.023$