MEDAL GIVEN:
A shipment of marbles with a mean diameter of 27 mm and a standard deviation of 0.15 mm is normally distributed. By how many standard deviations does a marble with a diameter of 26.85 mm differ from the mean?

A. 0
B. 0.15
C. 1
D. 2

Question

MEDAL GIVEN:
A shipment of marbles with a mean diameter of 27 mm and a standard deviation of 0.15 mm is normally distributed. By how many standard deviations does a marble with a diameter of 26.85 mm differ from the mean?

A. 0
B. 0.15
C. 1
D. 2

mathmale · Answer

Calculate the appropriate z-score:$$z=\frac{ x-\mu }{\sigma }$$

mathmale · Answer

Follow that formula like a road map.  What  is the x value in question?  The mean?  The standard deviation?  The formula I've mentioned includes all of the constants and variables I've given you.

alexandrad · Answer

so Z = 27 - 0.15 over 26.28

mathmale · Answer

Please review the meanings of the variables used here:$$z=\frac{ x-\mu }{\sigma }$$   What does each represent?  Why would you put 26.28 in the denominator?

mathmale · Answer

z=     z-score.  It's your goal to find the number of z-scores below the mean that the raw score 26.85 lies.

mathmale · Answer

I need to see your work.  The answer is not A.  Please work on understanding the math involved, not just on coming up with an "answer."

alexandrad · Answer

okay so z is 26.85 right ?

alexandrad · Answer

so 27-0.15 goes over (divided by) whatever that answer is ?

alexandrad · Answer

i just dont understand the formula and the order its supposed to go its my first time seeing and using this formula