Answer:
x = -2
Step-by-step explanation:
Answer
What expression represents her age 7 years from now?
y =x+7x
Two years ago?
z=y-2x
Step-by-step explanation:
Answer:
0.620
Step-by-step explanation:
We know that 1 feet = 12 inches, so, 5 feet is equivalent to 60 inches. Then, we are looking for the probability that a typical female from this population is between 60 inches and 67 inches. We know that
= 65.7 inches and
= 3.2 inches
and the normal density function for this mean and standard deviation is
![\frac{1}{\sqrt{2\pi } 3.2}exp[-\frac{(x-65.7)^{2}}{2(3.2)^{2}} ]](https://tex.z-dn.net/?f=%5Cfrac%7B1%7D%7B%5Csqrt%7B2%5Cpi%20%7D%203.2%7Dexp%5B-%5Cfrac%7B%28x-65.7%29%5E%7B2%7D%7D%7B2%283.2%29%5E%7B2%7D%7D%20%5D%20)
The probability we are looking for is given by
![\int\limits^{67}_{60} {\frac{1}{\sqrt{2\pi } 3.2}exp[-\frac{(x-65.7)^{2}}{2(3.2)^{2}} ] } \, dx =0.620](https://tex.z-dn.net/?f=%5Cint%5Climits%5E%7B67%7D_%7B60%7D%20%7B%5Cfrac%7B1%7D%7B%5Csqrt%7B2%5Cpi%20%7D%203.2%7Dexp%5B-%5Cfrac%7B%28x-65.7%29%5E%7B2%7D%7D%7B2%283.2%29%5E%7B2%7D%7D%20%5D%20%7D%20%5C%2C%20dx%20%3D0.620)
You can use a computer to calculate this integral. You can use the following instruction in the R statistical programming language
pnorm(67, 65.7, 3.2)-pnorm(60, 65.7, 3.2)