Complete Question
The complete qustion is shown on the first uploaded image
Answer:
The correct option is B
Step-by-step explanation:
From the question we are told that
The sample size is 
The mean is 
The standard deviation is 
Generally the standard error of this measurement is mathematically represented as
substituting values
ppb
Now the probability that the mean lead level from the sample of 49 measurements T is less than 15 ppb represented as P(X < 15 )
Next is to find the z value


Now checking the z-table for the z-score of -1 we have

I'm pretty sure the answer will be 6/10
Hope this helps, best of luck, terribly sorry if I'm wrong if I am my apologies
~Animaljamissofab ♥
-4 = 8m + 18n
-18n = 8m + 4
/-18 /-18 /-18
n = 8m/-18 + 4/-18
I'm not sure so yeah
The first one is 13 points and the 2nd one is 8. I'm pretty sure, hope this helps! :)