Answer:
14.63% probability that a student scores between 82 and 90
Step-by-step explanation:
Problems of normally distributed samples are solved using the z-score formula.
In a set with mean
and standard deviation
, the zscore of a measure X is given by:
![Z = \frac{X - \mu}{\sigma}](https://tex.z-dn.net/?f=Z%20%3D%20%5Cfrac%7BX%20-%20%5Cmu%7D%7B%5Csigma%7D)
The Z-score measures how many standard deviations the measure is from the mean. After finding the Z-score, we look at the z-score table and find the p-value associated with this z-score. This p-value is the probability that the value of the measure is smaller than X, that is, the percentile of X. Subtracting 1 by the pvalue, we get the probability that the value of the measure is greater than X.
In this problem, we have that:
![\mu = 72.3, \sigma = 8.9](https://tex.z-dn.net/?f=%5Cmu%20%3D%2072.3%2C%20%5Csigma%20%3D%208.9)
What is the probability that a student scores between 82 and 90?
This is the pvalue of Z when X = 90 subtracted by the pvalue of Z when X = 82. So
X = 90
![Z = \frac{X - \mu}{\sigma}](https://tex.z-dn.net/?f=Z%20%3D%20%5Cfrac%7BX%20-%20%5Cmu%7D%7B%5Csigma%7D)
![Z = \frac{90 - 73.9}{8.9}](https://tex.z-dn.net/?f=Z%20%3D%20%5Cfrac%7B90%20-%2073.9%7D%7B8.9%7D)
![Z = 1.81](https://tex.z-dn.net/?f=Z%20%3D%201.81)
has a pvalue of 0.9649
X = 82
![Z = \frac{X - \mu}{\sigma}](https://tex.z-dn.net/?f=Z%20%3D%20%5Cfrac%7BX%20-%20%5Cmu%7D%7B%5Csigma%7D)
![Z = \frac{82 - 73.9}{8.9}](https://tex.z-dn.net/?f=Z%20%3D%20%5Cfrac%7B82%20-%2073.9%7D%7B8.9%7D)
![Z = 0.91](https://tex.z-dn.net/?f=Z%20%3D%200.91)
has a pvalue of 0.8186
0.9649 - 0.8186 = 0.1463
14.63% probability that a student scores between 82 and 90
The image is missing so i have attached it.
Answer:
Volume = 1.5 litres
Step-by-step explanation:
Using pythagoras theorem, we can get the height (h) of the cylinder
14² + h² = 17²
h² = 289 - 196
h = √93
Now, volume of a cylinder is;
V = πr²h
In the image, r = diameter/2 = 14/2 = 7cm
Thus,
V = π × 7² × √93
V = 1485 cm³
Now, 1 litre = 1000 cm³
Thus, volume = 1485/1000 = 1.485 litres ≈ 1.5 litres
Answer:
60
Step-by-step explanation:
The standard form of the equation of a circle is (x-h)^2 + (y-k)^2 = r^2, where (h,k) is the center of the circle, (x,y) is a point of the circle, and r is the length of the radius of the circle. When the equation of a circle is written, h,k, and r are numbers, while x and y are still variables. (x-2)^2 + (y-k)^2 = 16 is an example of a circle. The problem gives us two of the three things that a circle has, a point (5,9) and the center (-2,3). We need to find the radius in order to write the equation. We substitute -2 for h, 3 for k, 5 for x, and 9 for y to get (5 - (-2))^2 + (9 - 3)^2 = r^2 We simplify: 49 + 36 = r^2, r^2 = 85. We only need to know r^2 because the equation of a circle has r^2. We now have all the information to write the equation of a circle. (x + 2)^2 + (y - 3)^2 = 85.