Answer:
True because 1/2 an hour is 30 minutes.
Step-by-step explanation:
 
        
                    
             
        
        
        
0 , -6 
6 , -12 
4 , -10 
-3 , -3 
These are the ones i could think of now 
        
             
        
        
        
Answer:
The probability that the diameter falls in the interval from 2499 psi to 2510 psi is 0.00798.
Step-by-step explanation:
Let's define the random variable, 
 "Comprehensive strength of concrete". We have information that 
 is normally distributed with a mean of 2500 psi and a standard deviation of  50 psi (or a variance of 2500 psi). In other words, 
.
We want to know the probability of the mean of X or 
 that falls in the interval 
. From inference theory we know that :

Now we can find the probability as follows:

Where 
, then:
