This is a square matrix whose entries are real and rows and columns are orthogonal unit vectors.
        
                    
             
        
        
        
Answer:
The 95% confidence interval for the percent of all coffee drinkers who would say they are addicted to coffee is between 21% and 31%.
Step-by-step explanation:
In a sample with a number n of people surveyed with a probability of a success of  , and a confidence level of
, and a confidence level of  , we have the following confidence interval of proportions.
, we have the following confidence interval of proportions.

In which
z is the zscore that has a pvalue of  .
.
The margin of error is:

A confidence interval has two bounds, the lower and the upper
Lower bound:

Upper bound:

In this problem, we have that:

Lower bound:

Upper bound:

The 95% confidence interval for the percent of all coffee drinkers who would say they are addicted to coffee is between 21% and 31%.
 
        
             
        
        
        
Answer:
The slope is m = 7/8 or 0.975
Step-by-step explanation:
 
        
                    
             
        
        
        
This is adding two vectors, one magnitude 300 direction east, and one magnitude 100 direction 30 degrees northeast.
For the resulting sum we can use the Law of Cosines or just add up the components.  Let's try it both ways.
Components first.   In the east direction we have
300 + 100 cos 30° = 300 + 100(√3/2) = 386.60 miles per hour
In the north direction we have
0 + 100 sin 30° = 100 (1/2) =  50 miles per hour
So a total speed of
sqrt{386.6^2 + 50^2} = 389.82 miles per hour
Answer: 389.82 
--------
OK let's try the Law of Cosines.   We have sides 300 and 100 and included angle 150°.


 
        
             
        
        
        
Answer:
∠ XZY ≈ 23.6°
Step-by-step explanation:
Using the sine ratio in the right triangle
sin Z =  =
 =  =
 =  , thus
, thus
Z =  (
( ) ≈ 23.6° ( to 1 dec. place )
) ≈ 23.6° ( to 1 dec. place )