Publications by Wingfeet
What is R-index
R index is developed in interpreting signal detection data for human perception. In sensory research it is used to interpret ranking data. The value one gets out of an R-index calculation is interpreted as a confusion between samples tested. It has been popularized among others by Bi and O’Mahony.The value of R-index ranges between ...
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Interpretation of R-index
Having introduced the R-index, it is time to look how it works. For this a simple example is sufficient. What happens if a product is different from another product. To make this at least slightly realistic, three products are needed. Two products will be equal, and one, the odd product, will have a varying distance. It is assumed, th...
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Russian elections
Just a few words about the Russian election. I read this entry http://www.badscience.net/2012/03/is-there-statistical-evidence-of-fraud-in-the-russian-election-data/ and thought to look for myself. For me it seems the data is not good enough to answer the fraud question.Downloading data, reading and just look:> r1 > head(r1) ...
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Detour in taste wordclouds
I read Mining Twitter for consumer attitudes towards hotels in my feed of R-bloggers. That reminded me that I intended to look at generating wordclouds for salt and MSG at some point. Salt, or sodium is linked to hypertension, which is linked to some diseases http://en.wikipedia.org/wiki/Complications_of_hypertension. It is a topic ...
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R index between two products is somewhat dependent on other products
I explained earlier how R-index is used in sensory is used to examine ranking data. The legitimization to use R-index is in the link with d’ and with Mann-Whitney statistic. In this post I show there is a dependence on the number of products and position of other products on the R index. It is a small effect. However, if data is an...
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Liking of apples – some data to link
I browsed through a paper by Peneau et al. (J. Sensory Studies, 2007) where they have nice data on apples; consumer evaluation, sensory evaluation and instrumental measurements. I think these are interesting data to examine if these variable blocks can be linked. This linking is a big thing in sensory science. In this post it is shown...
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Liking of apples – more than juiciness
In a previous blog it was shown using literature data that liking of apples was related to juiciness. However, there were some questionsIs the relation linear or slightly curved? The variation in liking around CJuiciness is large. Are more explanatory variables needed?So, what drives CJuiciness?In this post it becomes clear that inde...
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Linking apple liking to sensory
Previously it was seen that apple liking was related to consumers scores for juiciness and sweetness. It would be most nice if these scores can be linked to sensory scores. Thus a three block model would result:A block with sensory data describing how the apples tasteA block with consumer data describing how the apples are perceived b...
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Linking apples liking to analytical data
This post describes the last puzzle piece of the model. The link of instrumental to sensory data. Together with the previous pieces this leads to a model starting from physico-chemical measurements, to sensory data, to consumers’ perception and finally liking.In this post I choose to use generalized additive models (GAM). The aim is...
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Predicting apple liking from instrumental data
In this post I will examine if the individual models from previous posts together would make a good predictive model. Obviously, predictive capability is different from descriptive capability, predictions usually have a more simple model. As there was no test set the predictive capability will be analyzed using cross-validation. It sh...
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