Notes, abstracts, papers, exams and problems of Mathematics

Systematic Sampling: Type of Probability Sampling Method

In systematic sampling, sample members from a larger population are selected according to a random starting point but with a fixed, periodic interval. The sampling interval, calculated by dividing the population size by the desired sample size, determines the selection.

Oversampling: Techniques to Adjust Class Distribution

Oversampling is a data analysis technique used to adjust the class distribution of a data set, ensuring a balanced representation of different classes/categories.

P Value: Probability of Obtaining Extreme Test Results

The p value represents the probability of obtaining test results at least as extreme as the observed results during the test, assuming the null hypothesis... Continue reading "Understanding Systematic Sampling and Statistical Significance" »

In the examples C = {1,2,3,4} and D = {3,4,5}

SymbolMeaningExample{ }Set: a collection of elements{1,2,3,4}A ∪ BUnion: in A or B (or both)C ∪ D = {1,2,3,4,5}A ∩ BIntersection: in both A and BC ∩ D = {3,4}A ⊆ BSubset: A has some (or all) elements of B{3,4,5} ⊆ DA ⊂ BProper Subset: A has some elements of B{3,5} ⊂ DA ⊄ BNot a Subset: A is not a subset of B{1,6} ⊄ CA ⊇ BSuperset: A has same elements as B, or more{1,2,3} ⊇ {1,2,3}A ⊃ BProper Superset: A has B's elements and more{1,2,3,4} ⊃ {1,2,3}A ⊅ BNot a Superset: A is not a superset of B{1,2,6} ⊅ {1,9}A^cComplement: elements not in AD^c = {1,2,6,7}
When  = {1,2,3,4,5,6,7}A − BDifference: in A but not in B{1,2,3,4} − {3,4} =

By the Vertical Angles Congruence Theorem (Theorem 2.6), m∠4 = 115°. Lines a and b are parallel, so you can use the theorems about parallel lines.

m∠4 + (x + 5)° = 180° Consecutive Interior Angles Theorem

115° + (x + 5)° = 180° Substitute 115° for m∠4.
x + 120 = 180 Combine like terms.

x = 60 Subtract 120 from each side.7

By the Alternate Exterior Angles Theorem, m∠8 = 120°.
∠5 and ∠8 are vertical angles. Using the Vertical Angles Congruence Theorem
(Theorem 2.6), m∠5 = 120°.
∠5 and ∠4 are alternate interior angles. By the Alternate Interior Angles Theorem,
∠4 = 120°. So, the three angles that each have a measure of 120° are ∠4, ∠5, and ∠8.

By the Linear Pair Postulate (Postulate 2.8), m∠1 = 180° − 136° = 44°.

Unidad 7

 Dates/fechas-A numbered day in a month.*What's the date today?

Schedule/agenda.- To plan your tasks.*We have to schedule the flight.

Paper Diary/Agenda de papel-A traditional notebook where you write down Your tasks,important dates.*I use more the diary than the electronic planner.

Electronic planner/agenda electronica.- An electronic device in which information is stored.

Wall calendar /calendario de papel- It is a piece of paper Which contains 12 months divides in weeks and days.*I have to erase an appoiment in the wall calendar.

Up to date/actualizada.- Recent, It means something which contains the latest information.*I bought a diary to be up to date.

Appointment/cita de trabajo o medica.- A formal arrangement to Meet or visit.

Erase/... Continue reading "Flight Planning" »

Simple Random Sample

A sample designed in such a way as to ensure that (1) every member of a population has an equal chance of being included in the sample, and (2) every sample of size n has the same chance of occurring.

Selecting Elements

Subjects are selected at fixed sampling intervals by selecting every kth element thereafter. The interval between selections is determined by the ratio of the population size to the sample size (N/n). For example, if the population size is N=1,000 and a sample size of n=100 is desired, then the sampling interval is 1,000/100 = 10, so every 10th person is selected into the sample.

Different stages of Spain in the XIX

Packaging Aesthetics and Local Preferences

Packaging aesthetics are particularly important to the Japanese. Packaging is an important consideration for products that are Japanese prefer plain soft colors on their packages. People have local tastes based on their perceptions and attitudes about a products.

Product Innovation and Branding

Prior to 2004, Nokia launched different cell phone product-communication adaptation. Procter & Gamble recently introduced Pampers Rash Guard, a continuous innovation. Product problems initially policymakers in many parts of the world supported Suzlon. Regulators in different countries have proposed various the use of terms "light" and "natural" are allowed on labels only in the United States. Scotland is a... Continue reading "Global Packaging Aesthetics and Product Innovation" »