Stock returns vary from year to year. The more variance a stock displays the greater the potential risk. These are the rates of return for a stock over the last five years. Calculate the variance of these investment returns: 10, 30, 15, 5, 20. Hint: The variance of a series of numbers is the sum of the squares of their differences from the mean (average) of the numbers divided by the number of items in the series.

answer: it's d

step-by-step explanation:

answer: im gonna go with milli

step-by-step explanation:

the solution of the equation is 2.23 ⇒ answer b

step-by-step explanation:

* lets revise the meaning of exponential function

- the form of the exponential function is y = ab^x, where a ≠ 0, b > 0 ,  

  b ≠ 1, and x is any real number

- it has a constant base b

- it has a variable exponent x

- to solve an exponential equation, take the log or ln of both sides,  

  and solve for the variable

* lets solve the problem

∵

- the base is 7 and the exponent is x

- insert ㏑ in both sides

∴

- use the rule

∴ x ㏑(7) = ㏑(77)

- to find x divide both sides by ㏑(7)

∴

* the solution of the equation is 2.23 to the nearest 2 decimal places