Which formula is used to calculate the standard deviation of sample data?

H

-

1

2 (x1 - x)2+(x2-x)2 +...+(XN-6) 2

N

16--, (**)*(8=)*.- (89w=

X1-X

+

X2-X

+...+

X

-X

n-1

The diagram shows corresponding lengths in two similar figures. find the area of the smaller figure. a. 14.4 yd2 b. 24 yd2 c. 26.4 yd2 d. 28

Ariana starts with 100 milligrams of a radioactive substance. the amount of the substance decreases by 20% each week for a number of weeks, w. the expression 100(1−0.2)w finds the amount of radioactive substance remaining after w weeks. which statement about this expression is true? a) it is the difference between the initial amount and the percent decrease. b) it is the difference between the initial amount and the decay factor after w weeks. c) it is the initial amount raised to the decay factor after w weeks. d) it is the product of the initial amount and the decay factor after w weeks.

One cell phone plan charges $20 per month plus $0.15 per minute used. a second cell phone plan charges $35 per month plus $0.10 per minute used. write and solve an equation to find the number of minutes you must talk to have the same cost for both calling plans.