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
You multiply the constants 3 * 2 = 6
Add you add the exponents 6 + 1/2 = 13/2
So the answer is 6x^(13/2)
(D)
13.5 inches, because if you add 4.5x4 or 9x2 it equals 18, then you just subtract 4.5 from 18 and it’s 13.5
A day
= £9.20x7
= £64.40
6 days
£64.40x6= £386.40
The wages he has after he shared it with his mom
£386.40/7x5
= 55.20x5
= £276
£1932/£276= 7
It will take him 7 weeks to afford a car worth £1932.
The answer is D. -(4x-3)(5x-2)
