If the standard deviation for a set of data is 0, which of the following must be true?
a. all of the data values are negative.
b. all the data values equal 0.
c. all of the data values are identical.
d. none of the above must be true since the standard deviation cannot be equal to 0.

C. All of the data values are identical.

Step-by-step explanation:

If the standard deviation for a set of data is 0, then all of the data values are identical.

When a standard deviation is 0, then the variance is also 0 and the mean of the deviation that is squared is also 0, thereby making all the values identical to the mean, that is 0.

answer:  

step-by-step explanation:

here x represents the height of the pole,

and, the height of the shadow of the pole is 12 feet.

also, the angle of elevation from the top of the pole is 40°,

therefore,

by the low of sine,

which is the required equation for finding the value of x,

step-by-step explanation: