Answer:
Step-by-step explanation:
The goal to solving any equation is to have x = {something}. That means we need to get the x out from underneath that radical. It's a square root, so we can "undo" it by squaring. Square both sides because this is an equation. Squaring both sides gives you
Get everything on one side of the equals sign and set the quadratic equal to 0:
Throw this into the quadratic formula to get that the solutions are x = 5 and -8. We need to see if only one works, both work, or neither work in the original equation.
Does 
?
and
and 5 = 5. So 5 works. Let's try -8 now:
and
so
-8 = 8? No it doesn't. So only 5 works. Your choice is the third one down.
Answer:
0.022
Step-by-step explanation:
Given that :
Population size = 25000
n = 500 ; p = 0.4
Size of random sample (n) = 500
5% of population size : 0.05 * 25000 = 1250
Distribution is normally distributed since n < 5% of population size
Hence, the mean of the distribution = p = 0.4
Standard deviation = √((pq) /n)
q = 1 - p ; q = 1 - 0. 4 = 0.6
Standard deviation = √((0.4 * 0.6) /500)
Standard deviation = 0.0219089
= 0.022
First you add 1/2 and 3/4:
5/4n
5/4n = 12 so you divide both sides by 5/4
That gives you the answer of n= 9.6.
Hope this helped :)
Answer:
Step-by-step explanation:
Hello!
The variable of interest is:
X: number of daily text messages a high school girl sends.
This variable has a population standard deviation of 20 text messages.
A sample of 50 high school girls is taken.
The is no information about the variable distribution, but since the sample is large enough, n ≥ 30, you can apply the Central Limit Theorem and approximate the distribution of the sample mean to normal:
X[bar]≈N(μ;δ²/n)
This way you can use an approximation of the standard normal to calculate the asked probabilities of the sample mean of daily text messages of high school girls:
Z=(X[bar]-μ)/(δ/√n)≈ N(0;1)
a.
P(X[bar]<95) = P(Z<(95-100)/(20/√50))= P(Z<-1.77)= 0.03836
b.
P(95≤X[bar]≤105)= P(X[bar]≤105)-P(X[bar]≤95)
P(Z≤(105-100)/(20/√50))-P(Z≤(95-100)/(20/√50))= P(Z≤1.77)-P(Z≤-1.77)= 0.96164-0.03836= 0.92328
I hope you have a SUPER day!
The answer to your question is 7,600 fish
