Answer:

Step-by-step explanation:
z-score is denoted by:

here,
: mean
: standard deviation (or the square root of the variance)
so first we need to find the means of our sample:

Now to find the standard deviation we first need to find the variance of the sample. The variance is the sum of the squares of the differences of each value from the mean.

the standard derviation is simply the square root of the variance!

Now that we all the values for our z-score formula. we can plug it in!


Finally we'll use each value in place of x from our sample into the formula to find the z-score of each value.





We can even display the z-scores in a table: (the x-values are in ascending order)

Answer:
Step-by-step explanation:
list of prime numbers from 1-21
2,3,5,7,11,13,17,19
he has 21 students
the only numbers he can divide by is 3 and 7
21/3=7
21/7=3
They are at the same position at 0.5 seconds because with respect to the ocean's surface, they are both 9 feet away.
Hope this helps!!
Answer:
Kristen is correct.
2^3 is the same thing as 2 times 2, times 2. 2 cubed = 8.