Answer:
The sample required is ![n = 135](https://tex.z-dn.net/?f=n%20%3D%20135)
Step-by-step explanation:
From the question we are told that
The standard deviation is ![\sigma = 9](https://tex.z-dn.net/?f=%5Csigma%20%3D%209)
The margin of error is ![E = 2](https://tex.z-dn.net/?f=E%20%3D%20%202)
Given that the confidence level is 99% then the level of significance is mathematically evaluated as
![\alpha = 100-99](https://tex.z-dn.net/?f=%5Calpha%20%3D%20%20100-99)
![\alpha = 1 \%](https://tex.z-dn.net/?f=%5Calpha%20%3D%20%201%20%5C%25)
![\alpha = 0.01](https://tex.z-dn.net/?f=%5Calpha%20%3D%20%200.01)
Next we will obtain the critical value
from the normal distribution table(reference math dot armstrong dot edu) , the value is
![Z_{\frac{\alpha }{2} } = Z_{\frac{0.05 }{2} } = 2.58](https://tex.z-dn.net/?f=Z_%7B%5Cfrac%7B%5Calpha%20%7D%7B2%7D%20%7D%20%3D%20%20Z_%7B%5Cfrac%7B0.05%20%7D%7B2%7D%20%7D%20%3D%20%202.58)
The sample size is mathematically represented as
![n = [ \frac{Z_{\frac{\alpha }{2} } * \sigma }{E} ]^2](https://tex.z-dn.net/?f=n%20%3D%20%5B%20%5Cfrac%7BZ_%7B%5Cfrac%7B%5Calpha%20%7D%7B2%7D%20%7D%20%2A%20%20%5Csigma%20%7D%7BE%7D%20%5D%5E2)
substituting values
![n = [ \frac{ 2.58 * 9 }{2} ]^2](https://tex.z-dn.net/?f=n%20%3D%20%5B%20%5Cfrac%7B%202.58%20%2A%20%209%20%7D%7B2%7D%20%5D%5E2)
![n = 135](https://tex.z-dn.net/?f=n%20%3D%20135)
Answer:
B. 2 3/4 lbs
Step-by-step explanation:
there ar 16 ticks on a scale, the pointer is on 12, meaning it is 12/16, whihc is answer b
Answer:
perimeters of the rectangle=p=46.014 metres
Step-by-step explanation:
Given that:
Length (l) = 21 m
Area of rectangle(A) = 42.15 meter-square
Width (w)=?
Required data:
Perimater of Rectangle=p=?
Calculation:
As we know that Area of rectangle=A=l*w
Putting the value we get
42.15 m(square)=(21 m)*w
or w=42.15/21
or w=2.007 m
Now to find perimters of rectangle we know that
p=2(l + w) metres
putting the values
p=2(21+2.007) metres
p=2(23.007) metres
p=46.014 metres
Begin by multiplying $15.65 by 0.20 to find what 20% of the regular price is. This gives you 3.13, which in this situation means $3.13.
To find the price with discount subtract 15.65-3.13. This gives you $12.52.
To find out the change, subtract 20-12.52. This gives you $7.48.
So, he will receive $7.48 in change.
Hope this helps!
Only the second one
when diameter is 4 r=2
so 2pi*2=2²*pi the first is circumference the second area