D -9 because it has a -3 and its going to be the same - sign
You didn’t add any pictures so how could i help you with this?
Answer:
none
Step-by-step explanation:
I can answer the first four
1 is 40%
2 is 60
3 is $1.35
4 is 6%
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 ![[2499;2510]](https://tex.z-dn.net/?f=%5B2499%3B2510%5D)
. From inference theory we know that :
Now we can find the probability as follows:
Where 
, then:
