Answer:
The 99% confidence interval is 
Step-by-step explanation:
From the question we are told that
The sample size is 
The sample mean is 
The standard deviation is 
Given that confidence is 99% then the level of significance is mathematically represented as


Next we obtain the critical values of
from the normal distribution table
The value is
Generally the margin for error is mathematically represented as

=> 
=> 
The 99% confidence interval is mathematically represented as

=> 
=> 
Distribute the negative:
6x-3-8x-11
Combine like terms:
-2x-14
Simplify by factoring:
-2(x+7)
The answer is 1/2. Multiply 3/4 by 2/3.
Answer:
If we are choosing students at random from all students who got a B:
Total number of non-female students who got a B: 19
Total number of students who got a B: 36
Probability: 19/36
If we are choosing students at random from all students:
Total number of non-female students who got a B: 19
Total number of students: 78
Probability: 19/78