Answer:
a
The distribution of X is normal
b
c
Step-by-step explanation:
From the question we are told that
The population mean is
The standard deviation is
Generally given from the question that the amount of time spent alone by the population size is normally distributed then then the distribution of X (i.e the amount of time spent by the sample size (the one Mercurian)) will be normally distributed
Generally the probability that the child spend less than one hour in a day is mathematically represented as
Here
So
From the z-table the value of
So
Generally the percentage of children that spends over 3.5 hours unsupervised is mathematically represented as
From the z-table the value of
So