Answer:


The confidence interval of standard deviation is:
to 
Step-by-step explanation:
Given

See attachment for the formatted data
Solving (a): The mean
This is calculated as:

So, we have:




Solving (b): The standard deviation
This is calculated as:




--- approximated
Solving (c): 95% confidence interval of standard deviation
We have:

So:



Calculate the degree of freedom (df)



Determine the critical value at row
and columns
and 
So, we have:
---- at 
--- at 
So, the confidence interval of the standard deviation is:
to 
to 
to 
to 
Answer:
There is exactly one more real solution or there is exactly one more complex solution
Step-by-step explanation:
A quadratic equation is a polynomial of degree two
What this means is that a polynomial has two answers.
Now, from the question, we have an answer already which is a real root
Then the other answer which we do not have can take the form of two answers
It can either be a complex root or other wise be a real root
So the answer to this question is that ;
There is exactly one more real solution or there is exactly one more complex solution
Answer:
The equation of the line that is parallel to the line x = -2 and passes through the point (-5, 4) is x=-5
Option A is correct.
Step-by-step explanation:
We need to find equation of the line that is parallel to the line x = -2 and passes through the point (-5, 4)
We need a line parallel to x=-2 or x+2=0 it should be of form x+k=0
We need to find k, by putting value of x=-5 as given in question the point(-5,4)
-5+k=0
k=5
So, the equation of line will be found by putting k=5:
x+k=0
x+5=0
x=-5
So, the equation of the line that is parallel to the line x = -2 and passes through the point (-5, 4) is x=-5
Option A is correct.
Answer:
Morning's average rate = 50 mph, and Afternoon's average rate = 25 mph.
Step-by-step explanation:
Suppose he drove 150 miles for X hours, then his average rate in the morning was (150/X) mph.
Given that he spent 5 hours in driving.
And he drove 50 miles for (5-X) hours, then his average rate in the afternoon was 50/(5-X) mph.
Given that his average rate in the morning was twice his average rate in the afternoon.
(150/x) = 2 * 50/(5-x)
150/x = 100/(5-x)
Cross multiplying terms, we get:-
150*(5-x) = 100*x
750 - 150x = 100x
750 = 100x + 150x
750 = 250x
x = 750/250 = 3.
It means he spent 3 hours in the morning and 2 hours in the afternoon.
So morning's average rate = 150/3 = 50 mph.
and afternoon's average rate = 50/(5-3) = 25 mph.