$n=(\dfrac{z_c\cdot \sigma}{E})^2$ , where $\sigma$ is the population standard deviation, $z_c$ is the z-value for the $(1-\alpha)$ confidence interval and E is the margin of error .

As per given , we have

Population standard deviation : $\sigma=5.1$

z-value for 95% confidence interval : $z_c=1.960$

Margin of error : E= 3

Then, the required minimum sample :-

$n=(\dfrac{(1.96)\cdot (5.1)}{3})^2\\\\\Rightarrow\ n=(3.332)^2=11.102224\approx12$

Hence, the required minimum sample size = 12

3 0

2 years ago

Jessica and Raphael are saving money for concert tickets. Jessica has $20 and saves 10 per week.

Burka [1]

They have the same amount on week 5 ($70)
The Answer would be: $70
((Got this correct on my quiz, If you need it explained, It is below))
The easiest way to do this is to not pay attention to the y=x equation, because the solution is already in the information, this may confuse you and youre wasting time to solve it. Jess has $20 BEFORE saving and gets $10 WEEKLY, Raph has $40 BEFORE saving and gets $6 WEEKLY. In the chart/information, add the amount it takes to get Jess up to $40 then add $10 for every week on going until both their balances are equal. They match on the 5th week with $70 // If the information is different substitute the names/numbers/etc. Hope this helped you and anyone else looking for the answer!

8 0

3 years ago

F(x)=x^2(x+3)^2 <br><br> How do I find the roots of this equation?

Genrish500 [490]

= x^2 ( x+3 ) (x+3)
= set equal to 0

X^2= 0
X=0

X+3=0
X=-3

Answer is -3 and 0

6 0

2 years ago