Grandma and Grandpa are the subjects of this sentence. Why? Because they are the ones who did the action, which is that they "came to visit"
Answer:
24 months
Step-by-step explanation:
Lifespan with z-score of -3 in the the set of normally distributed life spans of an appliance can be calculated using the equation:
where
- X is the lifespan we are looking for
- M is the mean life span of the appliance (48 months)
- s is the standard deviation of the distribution of the life spans (8 months)
We have
that is
-24=X-48 and
X=24 months.
The life span of an appliance that has a z-score of -3 is 24 months.