Appropriate Measures of Central Tendency Nominal variables Mode Ordinal variables Median Interval level variables Mean - If the distribution is normal (median is better with skewed distribution)
Appropriate Measures of Central Tendency
Dec 31, 2015
Appropriate Measures of Central Tendency. Nominal variables Mode Ordinal variables Median Interval level variables Mean - If the distribution is normal (median is better with skewed distribution). Central tendency and the shape of the distribution. - PowerPoint PPT Presentation
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Appropriate Measures of Central Tendency
Nominal variables Mode
Ordinal variables Median
Interval level variables Mean - If the distribution is normal (median is
better with skewed distribution)
Central tendency and the shape of the distribution
Ukuran Penyebaran
Suatu data yang mempunyai kecenderungan (tendensi) pusat misalnya rata-rata yang sama belum tentu mempunyai penyebaran data yang sama pula.
Ukuran penyebaran (variasi) menyatakan seberapa jauh nilai amatan yang sebenarnya menyimpang atau berbeda dengan nilai pusatnya.
kegunaan dari ukuran variasi ini : untuk mengetahui seberapa jauh observasi melenceng dari nilai rata-ratanya.
How well does the mean represent the scores How well does the mean represent the scores in a distribution? The logic here is to in a distribution? The logic here is to determine determine how much spreadhow much spread is in the scores. is in the scores.
How much do the scores "deviate" from the How much do the scores "deviate" from the mean? Think of the mean as the mean? Think of the mean as the true scoretrue score or or as your as your best guessbest guess. .
If every X were very close to the Mean, the If every X were very close to the Mean, the mean would be a very good predictor. mean would be a very good predictor.
If the distribution is very sharply peaked then If the distribution is very sharply peaked then the mean is a good measure of central the mean is a good measure of central tendency and if you were to use the mean to tendency and if you were to use the mean to make predictions you would be right or close make predictions you would be right or close much of the time. much of the time.
The larger the standard deviation figure, the wider the range of distribution away from the measure of central tendency
Ukuran-Ukuran Penyebaran
Range (Jangkauan)Merupakan selisih nilai observasi tertinggi
dengan nilai observasi terendah.Contoh
VariansiVariansi populasi
Contoh :Tentukan variansi dari 5, 7, 2, 2, 4 !Peny :Rata-rata =5Variansi = 4.5
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