Answer: 0.345
Step-by-step explanation:
Given : The incomes of families in Newport Harbor are normally distributed with Mean : and Standard deviation :
Samples size : n=4
Let x be the random variable that represents the incomes of families in Newport Harbor.
The z-statistic :-
For x= $800,000
By using the standard normal distribution table , we have
The probability that the average income of these 4 families exceeds $800,000 :-
Hence, the probability that the average income of these 4 families exceeds $800,000 =0.345