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!
Answer:
The answer is D. g(x) = (x+4)^2 - 2
Step-by-step explanation:
This is because f(x) = (x-h)^2 + k
where h = horizontal translations and k = vertical translations
Answer:
2y = x + 2
Step-by-step explanation:
Looking at the graph, we can see from one point to the next (from right to left), the x-value rises by 2 and the y-value by 1;
From this we can work out the gradient between two points using the formula, i.e. the change/difference in y divided by the change/difference in x:
Joining the points gives a straight line, which means a constant gradient of ¹/₂
Use the line equation formula to get the function:
y - y₁ = m(x - x₁)
m = ¹/₂
x₁ = 0
y₁ = 1
y - 1 = ¹/₂.(x - 0)
y - 1 = ¹/₂.x
2y - 2 = x
2y = x + 2
