Answer: A. 664
Step-by-step explanation:
Given : A marketing firm is asked to estimate the percent of existing customers who would purchase a "digital upgrade" to their basic cable TV service.
But there is no information regarding the population proportion is mentioned.
Formula to find the samples size , if the prior estimate to the population proportion is unknown :
, where E = Margin of error.
z* = Two -tailed critical z-value
We know that critical value for 99% confidence interval = 
[By z-table]
Margin of error = 0.05
Then, the minimum sample size would become :
Simplify,
Thus, the required sample size= 664
Hence, the correct answer is A. 664.
Answer:
Angle EDC = Angle ADC
(Reflexive property)
ABD ~ ECD because all angles are congruent
If two are congruent, third one has to be as well since total angle is 180 each
Answer:
Step-by-step explanation:
We khow that the equation of a circle is written this way :
(x-a)²+(y-b)²=r² where (x,y) are the coordinates of the cercle's points and (a,b) the coordinates of the cercle's center and r the radius .
Our task is to khow the values of a and b :
- We khow that the center is lying on the line 3x+2y=16⇒ 2y=-3x+16⇒ y=
x+8 - We khow that the points P and Q are two points in the cercle
- Let Ω be the center of this cercle
- we can notice that : PΩ AND QΩ are both equal to the radius ⇒ PΩ=QΩ= r
- So let's write the expression of this distance using vectors KHOWING THAT Ω(a,b)
- Vector PΩ(a-4,b-6) and Vector QΩ(a-8,b-2)
- PΩ=
and QΩ=
- Let's substitute a by x and b by y
- PΩ=QΩ we substitute each distance by its expression
- After simplyfying the expressions we get finally : -12+8x-8y=0
- now we have -12x +8x-8y=0 and the line equation 3x+2y-16=0
- these are simultanious equations so after solving them we get x=3.8 wich is approximatively 4 and y=2
- we substitute a by 4 and y by 2 in PΩ to get the radius
- we get r =
= 4 - so r²= 16
- then the equation is : (x-4)²+(y-2)²=16
Answer:
She was finished with dinner at 6:50
Step-by-step explanation:
3:45 + 2 = 5:45
5:45 + 30 = 6:05
6:05 + 45 = 6:50
Answer:
C; 17.156
Step-by-step explanation:
a rational number is a number you could put in a ratio or fraction
