1. A relative measure of dispersion
2. Adjusts for differences in magnitudes of the means.
3. Does not have units of measure
4. Allows for direct comparisons of mean-adjusted dispersion across different data sets.

Percentiles and quartiles

Coefficient of determination
The proportion of variation in the dependent variable ”explained” by the independent variable.

Ex. Monthly income how much u spend on grocery, coefficient of determination 81%of your grocery billi being
19:% is not being explained(for reason we don’t know)
Maybe holiday month, having food, people….etc
Unexplained situation

CV fund 1 S/x=1.51
CV fund 2 S/x=1.30
Conclusion: Fund1 has greater relative dispersion than fund2

CH5.
Be familiar with the terms (different types of collect data) 1) Direct observation
2) Experiments
3) Survey
4) Telephone interviews
5) Self administered survey
--------------------------------------------------------------------------------------- Slope rise/run, y/x
B1=2.25 2.25/1 = y/x
Every 1 unit 2.25 cents

B1=0.3 0.3/1=y/x
Slope intercept b0=9.5

Data collection
1) Simple random sampling everyone has equal chance)
2) Stratified random sample (is supposed to be the most precise sampling, it doesn’t always work that way) Ex. 2008 election year, elected Obama, stratified sample it picked Obama as the winner, Hilary Clinton 3%, ex. 4 men 4 women

how? Divide take random sample

a cluster sample (save you money when u got large group to do it) Ex. Government use
randomly select some zip code
randomly selec out of my zip code
from this to that will do simple random sample
convenient sample

...Brandon Foster
MAE466
2/8/12
HW#2
1) I think about 1000 radial stations are required for a converged calculation.
2) The first plot is of a rotor with linear twist showing the lift coefficientvariation with rbar in hover. The second plot is the lift coefficient max along the radius which looks to be about 1.2.
The maximum thrust of the rotor in hover in terms of thrust coefficient is 0.0183.
Cpo = 2.5668e-004
Cpi = 0.0020
Cpt = 0.0022
Cpideal = 0.0017
Fig Mer = 0.7832
MATLAB CODE:
First Code:
This function integrates using the composite trapezoidal method of a function f(x) that is given in a set of n discrete points.
function I = IntPointsTrap(x,y)
n = length(x)-1
a = x(1)
b = x(n+1)
h = (b-a)/n
s = 0
for i = 2:n
s = y(i)+s;
end
I = h/2*(y(1)+y(n+1))+h*s
Second Code: s=sigma t=theta l=lambda a=alpha
B = 4;
rbar = .001:0.001:1;
s = .1; a = (2.*pi)./(sqrt(1 - .4.*(rbar.^2))); t0 = 0.3; t1 = -.17;
t = t0 + t1.*rbar;
li = -(1/2).*((s.*a)./(8))+(sqrt((((s.*a)./(16)).^2)+((s.*a.*rbar.*t)./(8))));
f = (B./2).*((1-rbar)./li)
F = (2./pi).*acos(exp(-f));
l = -(1/2).*((s.*a)./(8.*F))+(sqrt((((s.*a)./(16.*F)).^2)+((s.*a.*rbar.*t)./(8.*F))));
phi = l./rbar;
ab = theta - phi;
Cl = a.*ab;
plot(rbar, Cl)
dCt = (s./2).*Cl.*(rbar.^2)
y = dCt(1:999);
x = rbar(1:999);
I = IntPointsTrap(x,y);
Ct =I
Cd = .0091 - .078.*ab +...

...Homework 1 Due Monday, September 17th at the beginning of class. Show your work. 1. Match the diﬀerential equation in (a)-(c) to a family of solutions in (d)-(f). The point of this exercise is not to solve the diﬀerential equations in a) - c). (a) y = y 2 (b) y = 1 + y 2 (c) yy = 3x (d) y = tan(x + C) (e) 3x2 − y 2 = C (f) y = −1/(x + C)
2. Find the value of k so that y = e3t + ke2t is a solution of y − 2y − 3y = 3e2t . 3. Solve the following diﬀerential equations and IVP’s. You may solve these equations implicitly. (a) y + 3x2 y = x2 (b) y ln t = y+1 t
2
dy dt
2 sin t dy = 0 y (d) y y − t = 0, y(1) = 2, y (1) = 1 (c) cos t dt + 1 + (e) y − y = et y 2 (f) cos(xy) − xy sin(xy) + 2xyex + (ex − 2y − x2 sin(xy))y = 0, y(1) = 0 dy x + 3y (g) = dx 3x + y 2 x sin x dy + (y cos3 x − 1) dx = 0, 0 < x < π (h) cos (i) (x + yey/x )dx − xey/x dy = 0, y(1) = 0 [Hint: Think homogeneous.] 4. Suppose the diﬀerential equation dP = (k cos t)P, dt is a model of the human population P (t) of a certain community, where k is a positive constant. Discuss a (non-morbid) interpretation for the solution of this equation. In other words, what kind of population do you think it describes? [Actually solving the equation is not helpful.] 5. Write down a diﬀerential equation for the velocity v(t) of a falling body of mass m if air resistance is proportional to the square of the instantaneous velocity. (Remarks: Consider the forces acting on a falling object, and what they must add up to by...

...Understanding the Pearson Correlation Coefficient (r)
The Pearson product-moment correlation coefficient (r) assesses the degree that quantitative variables are linearly related in a sample. Each individual or case must have scores on two quantitative variables (i.e., continuous variables measured on the interval or ratio scales). The significance test for r evaluates whether there is a linear relationship between the two variables in the population. The appropriate correlation coefficient depends on the scales of measurement of the two variables being correlated.
There are two assumptions underlying the significance test associated with a Pearson correlation coefficient between two variables.
Assumption 1: The variables are bivariately normally distributed.
If the variables are bivariately normally distributed, each variable is normally distributed ignoring the other variable and each variable is normally distributed at all levels of the other variable. If the bivariate normality assumption is met, the only type of statistical relationship that can exist between two variables is a linear relationship. However, if the assumption is violated, a non-linear relationship may exist. It is important to determine if a non-linear relationship exists between two variables before describing the results using the Pearson correlation coefficient. Non-linearity can be assessed visually by examining a scatterplot of...

...Variations in Humans
Aim: To find the differences in human size from measurement
Apparatus: Seven to five friends, measuring tape
Method:
1. Choose five/seven friends
2. Take height of each person
3. Record data in appropriate manner
4. Process data collected
5. Make evaluation
Observation: The males in most case were taller than the females and had a general height of 5 feet 8 inches, while the females remained in the area of 5 feet and 1 inch to 5 feet and 2 inches.
Theory: Every human is not the same there are slight to major variations in size with every human being. Human variability, or human variation, according to the Wikipedia online encyclopedia is the range of possible values for any measurable characteristic, physical or mental, of human beings. Differences can be trivial or important, transient or permanent, voluntary or involuntary, congenital or acquired, genetic or environmental.
Analysis of data: The general height for males was about 5 feet 8 inches with only two exceptions being half and third of an inch taller. The females however were much shorter the tallest being 5 feet 2 inches. Height with the males may have shifted a little based on head shape and body structure, whereas the females having much more hair could’ve added the extra inches of difference.
Source of error: Shoes and hair could cause inaccurate measurements, poor posture and cranium structure. Tape measure may not have...

...CHEM 28.1
Experiment 1 – Application of Statistical Concepts in the Determination of Weight Variation in Samples
BANGAYAN, John Carlo B
2011-39545
BS Materials Engineering
Co-worker: Cervantes, Kerr
RESULTS AND DISCUSSION
Table 1. Weight of Samples
Sample
Weight
1
5.3380 g
2
5.3804 g
3
5.3580 g
4
5.5058 g
5
5.4045 g
6
5.3998 g
7
5.4030 g
8
5.4743 g
9
5.5249 g
10
5.4220 g
Data Set 1
Data Set 2
The Standard Deviation is a tool used in order to determine conciseness or closeness between data values. It provides a measure of how much variation is present between these values and the mean or the expected value. Simply speaking, the standard deviation plays an important role in one of the first steps in determining how precise the gathered data values are.
The Confidence Limits/Intervals test the validity of measurements. The intervals act as “reliable” estimates of the true value of the population parameter. The term “interval” implies that the confidence interval has the capability to contain in its range the true value depending on the confidence level desired by the researcher. Confidence levels reflect corresponding significance levels. For instance, 95% confidence level was used in the statistical computations in the experiment which reflects a significance level of 0.05.
The Q-test was used to determine acceptability of certain suspicious data values. It is an objective...

...Though he promised to work with Congress, the President also made clear that he would search for ways to go around them "whenever and wherever I can" if they do not cooperate. The President mentioned the College Opportunity Summit, which DSpar attended, to work on making college education a reality for all students. The President then received a thumbs up from Speaker Boehner after a reference to his humble beginnings as a barkeep's son. Boehner sat stone-faced the rest of the night.
Obama went on to support tax code reform to benefit companies that insource jobs back to the United States. Money saved from this reform would go towards improving infrastructure and creating more jobs. He announced his unwavering support for small businesses and technological innovation and encouraged Congress to undo cuts to research.
"Listen, China and Europe aren’t standing on the sidelines; and neither, neither should we. We know that the nation that goes all-in on innovation today will own the global economy tomorrow. This is an edge America cannot surrender."While Obama proudly declared that his "all of the above" energy plan is working to make energy independence a reality, he focused primarily on natural gas. While a step-up from foreign oil, natural gas is not always "extracted safely," i.e.fracking. He mentioned solar power and asserted that tax reform must prevent Big Oil from receiving $4 billion a year, so that this money can be invested in alternative fuel sources. And, to...

...algebraic expansion of powers of a binomial.
Figure 1 : Example use the binomial Expansion in geometric
There are 3 methods to expand binomial expression
Method 1 - Algebra method
Expansion two or more expression.
Example: The expansion depend on power value (n)
n = 0, (a + x)0 = 1
n = 1, (a + x)1 = a + x
n = 2, (a + x)2 = (a + x) (a + x) = a2 + 2ax + x2
n = 3, (a + x)3 = (a + x) (a + x) (a + x) = a3 + 3a2x + 3ax2 + x3
n = 4, (a + x)4 = (a + x)(a + x)(a + x)(a + x) = a4 +4a3x +6a2x2 +4ax3+ x4
Method 2 - PASCAL Triangle
Pascal's triangle is a triangular array of the binomial coefficients in a triangle. It is named after the French mathematician Blaise Pascal
Base on algebra method.
only using the coefficients of terms.
Power value Coefficient
n = 0 1
n = 1 1 1
n = 2 1 2 1
n = 3 1 3 3 1
n = 4 1 4 6 4 1
n = 5 1 5 10 10 5 1
n = 6 1 ? 1
Example:
(1 + 2x)5
n = 5 1 5 10 10 5 1
(1 + 2x)5 =
=
Method 3 - Binomial theorem
Sum of terms (Hasil tambah sebutan)
The general...

...
Coefficient of Friction- Post Lab
Abstract
The purpose of the experiment was to determine to coefficient of friction on a block sliding across a horizontal plane, and on the same block sliding down an inclined plane. This was done by first testing block, and how much weight on a string was needed to move the block at a constant velocity using a pulley system. The block weighed 0.2385 kilograms, and needed a hanging mass of 0.05 kg to move at a constant velocity. This means the coefficient of friction is 0.37. The second block was tested on an inclined plane, and the angle was found at which the block would move at a constant velocity. The angle found was 230. Using the equation μk=tan θk we found the friction to be 0.42. The friction was different because there was more force required to keep the block sliding down the plane at a constant velocity.
Introduction
Frictional forces are universal, in which they are found between two solid surfaces in parallel contact. If an object moves over a surface, the force exerted on the object by the surface is called the Kinetic friction force. This force is in a direction opposite the direction the object is moving. The friction force is proportional to the normal force exerted by the surface on the body. The force’s relationship can be viewed by using the coefficient of kinetic friction, μk, in f=μkn, where f is the magnitude of the force of the friction, and n is...

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