Determine the two z-scores that separate the middle 87.4% of the distribution from the area in the tails of the standard normal distribution.

The answer is:  " 6³ " .

Step-by-step explanation:

Note:  " (6)(6)(6) " ;  is the value of the  

[number "6" ; multiplied by that same number, "6" —two additional times;

   → so the same number, "6" ;  being multiplied:  "3 (three) times'

                 =  6 * 6 * 6  =  6³  ;  that is:  the number "6", raised to the third power (as an exponent);

    →  since: there are 3 (three) of the same numbers being multiplied;

            ⇒ hence the exponent, "3" .

The answer is:  " 6³ " .
 
Hope this helps!