Let
be the random variable for the number of marks a given student receives on the exam.
10% of students obtain more than 75 marks, so

where
follows a standard normal distribution. The critical value for an upper-tail probability of 10% is

where
denotes the CDF of
, and
denotes the inverse CDF. We have

Similarly, because 20% of students obtain less than 40 marks, we have

so that

Then
are such that


and we find

H(x) = -5x - 10
h(-2) = -5(-2) - 10
h(-2) = 10 - 10
h(-2) = 0
Answer: a+b+c/3
Step-by-step explanation:
mean= sum of all values/number of values
A: tracy's family has greater valiablity because put the number in order
Answer:
I think it is 30 inches
Step-by-step explanation: