5-12 ÷(6-2)-1
Do whats in the parenthesis
5-12 ÷4-1
Do division next
5- 3- 1 = 1.
Do the same for the next.
(4-3) x 2+15 ÷(6-1)
1 x 2+15 ÷5
2+15÷5
2+3= 5
The fraction would be - 3/5
Perimeter = sum of all sides
32 = 2(x+2) + 2(7)
32 = 2x+4 + 14
32 = 2x+18
14 = 2x
/2 /2
7 = x
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!
