Design

Experimental design bertalian dengan rencana umum untuk melaksanakan percobaan.

Suatu percobaan adalah suatu sarana untuk mengembangkan hubungan sebab-akibat antara event tertentu dalam suatu lingkungan dan kejadian dari suatu bentuk perilaku khusus.

Experimental design bertalian dengan rencana umum untuk melaksanakan percobaan.

Suatu percobaan adalah suatu sarana untuk mengembangkan hubungan sebab-akibat antara event tertentu dalam suatu lingkungan dan kejadian dari suatu bentuk perilaku khusus.

Experimen dilakukan untuk

1. Menyediakan dukungan emperis (berdasar fakta)/ bukti untuk suatu teori2. Menguji hipotesis yang berdasar suatu teori.3. Validasi hasil pengalaman dan eksperimen yang lebih dahulu

Experimen dilakukan untuk

1. Menyediakan dukungan emperis (berdasar fakta)/ bukti untuk suatu teori2. Menguji hipotesis yang berdasar suatu teori.3. Validasi hasil pengalaman dan eksperimen yang lebih dahulu

Suatu ilustrasi

Dua atau lebih kelompok diperla-kukan persis sama kecuali terhadap treatment percobaan.

Maka perbedaan yang dapat diamati pada kelompok tersebut disebabkan karena perlakuan tersebut.

Suatu ilustrasi

Dua atau lebih kelompok diperla-kukan persis sama kecuali terhadap treatment percobaan.

Maka perbedaan yang dapat diamati pada kelompok tersebut disebabkan karena perlakuan tersebut.

Hypotheses

The research hypotheses is a succinct (compressed into few words) statement of the purpose of the experiment.

The experiment is set up to manipulate independent variable and observe their effect(s) on the dependent variable(s) which will either confirm or reject the experimental hypotheses

Hypotheses

The research hypotheses is a succinct (compressed into few words) statement of the purpose of the experiment.

The experiment is set up to manipulate independent variable and observe their effect(s) on the dependent variable(s) which will either confirm or reject the experimental hypotheses

CONTOH

Users learn quicker with a structured rather than an unstructured interface.

Indedependent variable =type of interface

dependent variable =the number of errors made the; length of time to complete the task and users’ preference rating for the two interface

CONTOH

Users learn quicker with a structured rather than an unstructured interface.

Indedependent variable =type of interface

dependent variable =the number of errors made the; length of time to complete the task and users’ preference rating for the two interface

Differences in experimentaldesigns

Perbedaan didasarkan atas

1. Tipe dan jumlah subject yang terlibat di dalam experimen

2. Jumlah independen variabel, dan jumlah level pada variabel tsb.

3. Metode meletakkan treatment pada subject, within, between atau mix.

Differences in experimentaldesigns

Perbedaan didasarkan atas

1. Tipe dan jumlah subject yang terlibat di dalam experimen

2. Jumlah independen variabel, dan jumlah level pada variabel tsb.

3. Metode meletakkan treatment pada subject, within, between atau mix.

Pemilihan subject

A subject is person who participates in the experiment.

It is not advisable for the designers themselves to act as subjects for a number of reasons.

1. Apabila dibutuhkan jeneralisasi hasil penelitian untuk suatu populasi maka subject penelitian harus contoh acak dari populasi tersebut.

Pemilihan subject

A subject is person who participates in the experiment.

It is not advisable for the designers themselves to act as subjects for a number of reasons.



3. Ada perbedaan antara user (awam dan pakar), populasi yang akan diambil contoh acaknya berbeda sehingga sistem yang akan dikembangkan ….?


3. Ada perbedaan antara user (awam dan pakar), populasi yang akan diambil contoh acaknya berbeda sehingga sistem yang akan dikembangkan ….?

Yang perlu dipertimbangkan dalam pemilihan subject

1. Pengalaman yg dimiliki subject2. Tingkat ketrampilan subject

3. Jumlah subject yg diperlukan

Yang perlu dipertimbangkan dalam pemilihan subject

1. Pengalaman yg dimiliki subject2. Tingkat ketrampilan subject

3. Jumlah subject yg diperlukan

Faktor lain yang dimiliki subject yang harus diperhatikan berhubungan dengan kontrol adalah;

umur, pengalaman (komputer dan tugas), kecakapan, seks, handeness, motivasi dan anxiety.

If this factors are not systematically manipulated, berarti diperlakukan sebagai variabel independen, maka sering harus dikontrol

Faktor lain yang dimiliki subject yang harus diperhatikan berhubungan dengan kontrol adalah;

umur, pengalaman (komputer dan tugas), kecakapan, seks, handeness, motivasi dan anxiety.

If this factors are not systematically manipulated, berarti diperlakukan sebagai variabel independen, maka sering harus dikontrol

The avaibility of subjects is often an important constraining factor. The number of subjects is a matter of choise, but there are general rules. We need enough subjects to provide a relatively sentisitive test of the research hypotheses.

Sensitivity is concerned with the ability to detect differences when they area present.

The avaibility of subjects is often an important constraining factor. The number of subjects is a matter of choise, but there are general rules. We need enough subjects to provide a relatively sentisitive test of the research hypotheses.

Sensitivity is concerned with the ability to detect differences when they area present.

One way to increase sensitivity is to increase the number of subjects. However significant statistical results rely on the treatment variance being greater than expected by chance.

Generally, the minimum number of subjects in controlled experiment should be no less than six but the increase in sensitivity with ten subjects or more is considerable.

One way to increase sensitivity is to increase the number of subjects. However significant statistical results rely on the treatment variance being greater than expected by chance.

Generally, the minimum number of subjects in controlled experiment should be no less than six but the increase in sensitivity with ten subjects or more is considerable.

Desgning experiment

Designing HCI experiment involves at least the following1. Formulating the hypotheses2. Developing predictions from the hyp/3. Choosing a means to test the predictions4. Identifying all variables that might affect the results of the experiment5. Deciding which are the independent variables (and levels of the independent variable), dependent variable and which variables need to be controlled by some means

Desgning experiment

Designing HCI experiment involves at least the following1. Formulating the hypotheses2. Developing predictions from the hyp/3. Choosing a means to test the predictions4. Identifying all variables that might affect the results of the experiment5. Deciding which are the independent variables (and levels of the independent variable), dependent variable and which variables need to be controlled by some means

Desgning experiment

Designing HCI experiment involves at least the following

6. Designing the experiment task and method.7. Subject selection.8. Deciding the experiment design, data collection method and controlling confounding variables9. Deciding on the appropriate statistical or other analysis.10.Carrying out a pilot study (I.e prototype the experiment design)

Desgning experiment

Designing HCI experiment involves at least the following

6. Designing the experiment task and method.7. Subject selection.8. Deciding the experiment design, data collection method and controlling confounding variables9. Deciding on the appropriate statistical or other analysis.10.Carrying out a pilot study (I.e prototype the experiment design)

Confounding

The strength of the experimental method depends on the experimenter’s ability to guarantee that only the manipulated variables are permitted to vary systematically from condition to condition.

When a second or other variables is unwittingly permitted to vary along with the itended one, we say the the variable are confounded.

Confounding

The strength of the experimental method depends on the experimenter’s ability to guarantee that only the manipulated variables are permitted to vary systematically from condition to condition.

When a second or other variables is unwittingly permitted to vary along with the itended one, we say the the variable are confounded.

Confounding

dapat cokontrol dengan cara

1. Diberikan secara sama kesemua treatment2. Diacak dari subject ke subject

Confounding

dapat cokontrol dengan cara

1. Diberikan secara sama kesemua treatment2. Diacak dari subject ke subject

Assigning subject to different treatment contionsAssigning subject to different treatment contions

Between group designBetween group design

Group 1Interface AS1S2S3S4S5S6




Disebut juga sebagai independent-group design

Disebut juga sebagai independent-group design

Assigning subject to different treatment contions

Within group design





Disebut juga sebagai repeated measures


Within group designWithin group design

Are most efficient in that more information is obtained from each subject; this is important where time is limited and the availability of subjects is scarse. Are also appropriate where training is required.

The subject acts as their own control. Concequently the subject varaince is less and the design is more powerful

Are most efficient in that more information is obtained from each subject; this is important where time is limited and the availability of subjects is scarse. Are also appropriate where training is required.

The subject acts as their own control. Concequently the subject varaince is less and the design is more powerful

Within group designWithin group design

Usually require fewer total observations than the between group designs to achieve the same degree of sensitivity or statistical power.

The major problem is the carry-over effects. Carry-over, practice and range effects all affect subsequent user behaviour.Performance of the last task can be influenced due to having experienced the ealier conditions.

Usually require fewer total observations than the between group designs to achieve the same degree of sensitivity or statistical power.

The major problem is the carry-over effects. Carry-over, practice and range effects all affect subsequent user behaviour.Performance of the last task can be influenced due to having experienced the ealier conditions.


Mix factorial designMix factorial design

Group 1Interfacestyle - picturetrials 1,2,3,4S1S2S3S4S5S6

Group 1Interfacestyle - picturetrials 1,2,3,4S1S2S3S4S5S6

Group 2Interfacestyle - testtrials 1,2,3,4S7S8S9S10S11S12

Group 2Interfacestyle - testtrials 1,2,3,4S7S8S9S10S11S12


Mix factorial designMix factorial designA populer type of design, the carry-over effects are not so great and where subjects’ performance can be measured over a number trials on one of the independet variables. Invlove one or more independent variables being treated as within groups and also one other, or more independent variables being treated as between groups.

A populer type of design, the carry-over effects are not so great and where subjects’ performance can be measured over a number trials on one of the independet variables. Invlove one or more independent variables being treated as within groups and also one other, or more independent variables being treated as between groups.


Mix factorial designMix factorial designIn this example, the independent variables are interface style (2 levels) and trials (4 levels). The design is a 2x4 mixed factorial design. Interface style is between groups, while trials are repeated measures. Mix factorial design are particularly useful where learning is being manipulated along with another varible. Learning variables are best treated as repeated measures.

In this example, the independent variables are interface style (2 levels) and trials (4 levels). The design is a 2x4 mixed factorial design. Interface style is between groups, while trials are repeated measures. Mix factorial design are particularly useful where learning is being manipulated along with another varible. Learning variables are best treated as repeated measures. BACK TO HOME

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