Answer:
1,771.6 inches.
Step-by-step explanation:
As there are 13 girls and 15 boys in the class, there are a total of 28 students (13 + 15). Thus, while the average height of these is 161 cm, the total height in centimeters of all the students is 4.508 centimeters (161 x 28).
Now, 1 centimeter is equal to 0.393 inches. Thus, since 4.508 x 0.393 equals 1,771.6, the height in inches of the entire class measured together is 1,771.6 inches.
240 yards is how far they ran
Answer:
a. .92
Step-by-step explanation:
In a sample with a number n of people surveyed with a probability of a success of
, and a confidence level of
, we have the following confidence interval of proportions.
![\pi \pm z\sqrt{\frac{\pi(1-\pi)}{n}}](https://tex.z-dn.net/?f=%5Cpi%20%5Cpm%20z%5Csqrt%7B%5Cfrac%7B%5Cpi%281-%5Cpi%29%7D%7Bn%7D%7D)
In which
z is the zscore that has a pvalue of
.
The margin of error of the interval is:
![M = z\sqrt{\frac{\pi(1-\pi)}{n}}](https://tex.z-dn.net/?f=M%20%3D%20z%5Csqrt%7B%5Cfrac%7B%5Cpi%281-%5Cpi%29%7D%7Bn%7D%7D)
The lower bound is the point estimate
subtracted by the margin of error.
The upper bound is the point estimate
added to the margin of error.
Point estimate:
The confidence interval is symmetric, so it is the mean between the two bounds.
In this problem:
![\pi = \frac{0.372 + 0.458}{2} = 0.415](https://tex.z-dn.net/?f=%5Cpi%20%3D%20%5Cfrac%7B0.372%20%2B%200.458%7D%7B2%7D%20%3D%200.415)
Sample of 400, which means that ![n = 400](https://tex.z-dn.net/?f=n%20%3D%20400)
Margin of error is the estimate subtracted by the lower bound. So ![M = 0.415 - 0.372 = 0.043](https://tex.z-dn.net/?f=M%20%3D%200.415%20-%200.372%20%3D%200.043)
We have to find z.
![M = z\sqrt{\frac{\pi(1-\pi)}{n}}](https://tex.z-dn.net/?f=M%20%3D%20z%5Csqrt%7B%5Cfrac%7B%5Cpi%281-%5Cpi%29%7D%7Bn%7D%7D)
![0.043 = z\sqrt{\frac{0.415*0.585}{400}}](https://tex.z-dn.net/?f=0.043%20%3D%20z%5Csqrt%7B%5Cfrac%7B0.415%2A0.585%7D%7B400%7D%7D)
![z = \frac{0.043\sqrt{400}}{\sqrt{0.415*0.585}}](https://tex.z-dn.net/?f=z%20%3D%20%5Cfrac%7B0.043%5Csqrt%7B400%7D%7D%7B%5Csqrt%7B0.415%2A0.585%7D%7D)
![z = 1.745](https://tex.z-dn.net/?f=z%20%3D%201.745)
has a pvalue of 0.96.
This means that:
![1 - \frac{\alpha}{2} = 0.96](https://tex.z-dn.net/?f=1%20-%20%5Cfrac%7B%5Calpha%7D%7B2%7D%20%3D%200.96)
![\frac{\alpha}{2} = 1 - 0.96](https://tex.z-dn.net/?f=%5Cfrac%7B%5Calpha%7D%7B2%7D%20%3D%201%20-%200.96)
![\frac{\alpha}{2} = 0.04](https://tex.z-dn.net/?f=%5Cfrac%7B%5Calpha%7D%7B2%7D%20%3D%200.04)
![\alpha = 0.08](https://tex.z-dn.net/?f=%5Calpha%20%3D%200.08)
Confidence level:
![1 - \alpha = 1 - 0.08 = 0.92](https://tex.z-dn.net/?f=1%20-%20%5Calpha%20%3D%201%20-%200.08%20%3D%200.92)
So the correct answer is:
a. .92
Answer:
Basically we need to add all of the inches
Step-by-step explanation:
so...
8 inch ( first day ) + 6 inch ( second day) + 9 inch ( third day )
add all those inches together what do you get?
23 inches in total. So altogether 23 inches of snow fell during the 3-day storm
400+90+3
490+3
93+400
answer