Answer:
The 95% confidence interval is 
A 95% level of confidence mean that there is 95% chance that the true population mean will be in this interval
Step-by-step explanation:
From the question we are told that
The sample size is 
The mean is 
The standard deviation is 
Given that the confidence level is 95% then the level of significance is mathematically represented as

=> 
=> 
Next we obtain the critical value of
from the normal distribution table , the value is

Generally the margin of error is mathematically represented as

substituting values


The 95% level of confidence interval is mathematically represented as

substituting values


The 95% level of confidence mean that there is 95% chance that the true population mean will be in this interval
It’s likely scalene since none of the angles are the same
The answer is your looking for is 400
You solve for x and get x<-2 or x>= -1/2 and then graph
D the mathematical work shown sbove is correct as written