Achmad Mardiansyah's Journal

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Archive for the ‘statistics’ Category

Apa itu “mutually exclusive”?

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http://intmstat.com/counting-probability/mutually-exclusive.gif
Suatu hari di sebuah kelas engineering, ada rekan yang bertanya ke saya, “mutually exclusive itu apa sih?” setelah beberapa lama menjelaskan, rupanya dia ngak mengerti sebuah kalimat dari textbook english yaitu, “dimensions of quality are not-mutually-exclusive”.

Berarti untuk memahami kalimat tersebut, maka kita harus tahu dulu arti mutually exclusive. saya jawab dengan singkat, “mutually-exclusive artinya independent, jadi not-mutually-exclusive artinya tidak independent alias saling berhubungan“. temen saya pun tambah bingung, kok bisa yah? hehehe… Read the rest of this entry »

Ternyata begini yah kalo jadi batgirl (BATAK GIRL) itu?

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Ternyata begini yah kalo jadi batgirl (BATAK GIRL) itu? sebuah perjuangan dalam mencari batmannya…

Artikel dibawah ditulis oleh nancy margaretha, rekan kerja saya ketika dulu di SI. Nancy adalah seorang batgirl dimana suaminya bukan batman, melainkan dari negeri asing. tidak ada maksud untuk SARA di artikel ini…

selamat membaca… hehehhe 🙂

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Selama berbulan-bulan ini didera pertanyaan seperti ini;

“kenapa ga yang batak aja, kenapa harus bule?”

Bukan, bukan cuma gue aja yang dihantam badai pertanyaan gak penting kek gini.

“Emang ga ada orang Batak lagi, harus bule?”

Kami, cewe batak, kristen pula itu nasib perjodohannya paling buruk sedunia. (ya.. saya hanya membesar-besarkan kenyataan, supaya orang bisa kasian)

Pake logika aja dong…

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understanding: confidence interval, confidence level and number of sample

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Just want to share about an idea of understanding confidence interval, confidence level, and number of sample without being bothered by the formulas. I found many people are still confused about this.

here it is…

Suppose you join a shooting tournament, and your goal is to shoot a circle target in a given distance.
Shooting analogy
Statistics in research
Goal: to shoot a circle target in a given distance
Goal: estimate mean of population in the form of an interval.
Why interval? Because you don’t do a census. Therefore, the best thing that you can do is providing an interval, and hoping that the mean of population is in the interval
jury will mark your shoot
audience will comment on your research
Your gun: best sniper rifle
Your tool: doing sampling
Assume: environment is ideal: wind, rifle, bullets
Assume: sampling process is ideal
Size of target: measured by diameter
Mean of population: defined by interval. This is the confidence interval
you’ll feel more confident if the target is wider.
in here, the higher the confidence level, the wider the  interval will be. Because if you provide a wider interval, the higher probability of population’s mean appear in the interval. That’s why you feel more confident
unfortunately, the jury won’t allow you to widen the target size
the audience won’t like a wider estimation interval. They’ll think that your research is not accurate.
so, the target size is fixed, and so your confidence level.
here, you have to stick with your confidence level (let say 95%). You don’t want to be ashamed right?. You need to find out, how to shorten the estimation interval without decreasing confidence level.
one way to make sure that you can hit the target is by shooting more
here, you can produce a better result by increasing the number of sample because the more data the closer to the reality. Then, your audience will trust you more.

So, if you meet a beginner in statistics, this analogy could be of some help.

Regards,

Achmad Mardiansyah