Question 973394
mean is 207 and SD is 17

z=(x-mean)/SD
=(201-207)/17
want the value of z <(-6/17) or z< -0.353
This is 0.3620.  Intuitively, that makes sense.  About 16% of the probability is with a z-score <-1, so this should be more.

z=(x-mean(/sd/sqrt(n))    The probability should be much less, because the mean of 16 has to be less than 201, not just one.
=(201-207)/(17/4)=   (-6/4.25)
Now, the z< -1.411
Probability is 0.079, much less as expected

I can write 
z= (-6)*sqrt (37)/17   I have inverted the denominator here, and the sqrt (n) comes to the numerator.

z=-2.147
Probability is 0.0159.