Answer:
7.875......7.9.....or 8
Step-by-step explanation:
-3÷2×-21÷4= 7.875
63÷8=7.875
Answer:
c=12
Step-by-step explanation:
12c - 53= 91
12c=144
c=12
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:
The 80% confidence interval for difference between two means is (0.85, 1.55).
Step-by-step explanation:
The (1 - <em>α</em>) % confidence interval for difference between two means is:

Given:

Confidence level = 80%

*Use a <em>t</em>-table for the critical value.
Compute the 80% confidence interval for difference between two means as follows:

Thus, the 80% confidence interval for difference between two means is (0.85, 1.55).
Sin404 = sin(360 + 44)
as sin(360 + α) = sinα
= sin44