Answer:
B. 0
Step-by-step explanation:
=>d+(-d)
=>d-d
=>0
 
        
                    
             
        
        
        
Answer: 0.4758
Step-by-step explanation:
Given : Mean : 
Standard deviation : 
Also, the new population of pilots has normally distributed .
The formula to calculate the z-score :-

For x=130 lb .

For x=171lb.

The p-value =

Hence, the required probability : 0.4758
 
        
             
        
        
        
Answer:
D.34
Step-by-step explanation:
Let's the A be the 20th board counting from the top of the stack, and B be the 16th board counting from the bottom of the stack. If A is immediately below B, this means B is the 19th board counting from the top of the stack, and also there are 18 other boards that are above B. So the total number of board in the stack would be
16 + 18 = 34
D is the correct answer
 
        
             
        
        
        
Answer:
-93.5
Step-by-step explanation:
let the number be y
1/2 × y + 49 =2 1/4
y/2 +49 =9/4
y/2 =9/4-49
y/2 = 9-196/4 
y/2 = -187/4
cross multiply
4y = -374
y = -93.5
 
        
                    
             
        
        
        
Answer:
The true average mileage of the Libra  Using Null hypothesis is as ;
H0:μ≤26 
 (Ha):μ >26 
Step-by-step explanation:
Given:
 Libra, will average better than 26 miles per gallon in the city
To Find:
Average mileage of the Libra.
Solution:
This problem is related to the null hypothesis  and alternate hypothesis.
i.e Null Hypothesis is the statement which is true and statement which contradictory is called alternate hypothesis.
<em>“reject H0” if the sample information favors the alternative hypothesis.
</em>
<em>“do not reject H0” / “decline to reject H0” if the sample information is insufficient to reject the null hypothesis</em>
So given that condition is libra will have average better than 26 
So it will include 26 and above values .
i.e. True  condition is called as null hypothesis (H0)
so true average will be greater than 26 
So H0:μ≤26 
And the Alternate hypothesis will be the contradictory to true condition
 (Ha):μ >26 .