Testing means for my data set against the Pareto principle?

I am looking at an emarketing data set and am interested in the distribution of my revenue amongst customers who do make a purchase. As you may know, the Pareto principle would suggest that 80% of revenue comes from 20% of customers. For my data set (again, amongst only those who do buy) the top 20% of revenue-producers generate 60.1% of revenue ($297,119). One of my website channels (Google/Organic) is at 67.1%. Now I would like to test both 60.1% (total mean) and 67.1% against the 80% figure (and perhaps a lower one if that doesn’t work out) through a 90% confidence interval I was also thinking of running a paired t-test between the mean revenues of each of the major Source / Mediums of the top 20% to see if there is significant variance in the distribution of different source / revenues that would warrant further exploration. My BIGGEST concern here is violating assumptions/conditions. My data set is not really normal, a lot of the distribution are clustered around zero, etc. Can I run these tests? Do I have to convert the percentages into counts? For reference, here is my data set: https://docs.google.com/spreadsheets/d/1pIapZXgaScU44SFhwOaBcM1BBURvTB4p6wjSre5OP2Q/edit?usp=sharing submitted by /u/T00Human [link] [comments]

The standard error of the estimate

Hi, I habe a question: where is the difference between the standard error of the estimate and the standard error reported for example for the slope of a regression line?

Which is the difference between the ”standard error” and standard error of the estimate?

The standard error of the estimate is a measure of the accuracy of predictions. The regression line is the line that minimizes the sum of squared deviations of prediction (also called the sum of squares error), and the standard error of the estimate is the square root of the average squared deviation.

submitted by /u/luchins
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[Statistics] Probability of a certain season result given the probability of winning each game

Hi all,

I’m trying to come up with a model for the probability of a certain season result in football (11-1, 4-8, etc.) given the probability of winning each game. I’ve gone through all the games in the CAA conference in FCS football, where my team plays, and given each game a winner and their probability of winning. You can find this in the google sheet below. Given these probabilities, how can I find the probability of a certain record at the end of the season? I’ve tried

(p)^k * (1-p)^(n-k) 

for k = number of wins a team would have in this scenario, and

n = number of total games

p = average probability of winning each game

This didn’t work. In the Albany tab, you can see the results I have for that method, and the probabilities don’t add up to 1, which tells me the methodology is flawed. What am I doing wrong here?


submitted by /u/InfusedStormlight
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Transposing issue

Hello all I am having an issue with a dataset.

So I have a table that looks like this:

Year t1 t2…
country1 variable1 48 49
country1 variable 2 49 50
country1 variable 3 38 53

But I need to reformat the table to look like this:

Year country variable 1 variable 2
t1 country1 48 49
t2 country1 49 50
t3 country1 70 51

When I transpose it does obviously does not work out perfectly:

year country 1 country 1
variable 1 variable 2
t1 48 49
t2 49 50

This is a large data set and importing the country column manually may take a lot of time. Is there an excel tool or add on I can use to reformat this table? Thought I would check before I do it the long way.

submitted by /u/Cloone11
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Anyone have any suggestions for good calculus-based statistic text books?

The only statistics class that my school offers is more of a remedial math course than anything else, so I thought that I’d just learn it on my own. I’m a computer science major, so I’m looking for something more geared towards applied statistics, but I’m still interested in the pure math portion of it as well. The university-level math courses that I’ve taken so far are calc 1-3 and elementary differential equations.

submitted by /u/Toxicpipluppz
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What recent motor industry decisions by a manufacturer would you have done differently and why?

For me, I would have done these things:

Infiniti leaving Europe

Like General Motors, the then-owner of Opel 35 years ago, I would have done a badge-swap.

In 1984, GM discontinued the Opel Senator, and rebadged it as Vauxhall Senator in the United Kingdom, since Opel was seen as sportier compared to Vauxhall.

The Infiniti Q50 would have become the Nissan Skyline, as with the version sold in Japan, since the Nissan Skyline name has greater brand equity and recognition than Infiniti [much like the Opel-to-Vauxhall decision above], and I would have restricted the range solely to the 2.0-liter/208hp 4-cylinder turbo and 3.5-liter/359hp V6 [combined output] gasoline-electric hybrid. The 2.2-liter/168hp 4-cylinder turbodiesel – badged as 2.2d – would have been discontinued in Europe, due to slow sales of diesel models.

Trim levels would have been changed from the current twelve versions: SE, Premium, Premium [Multimedia], Premium Executive, Premium Tech, Sport, Sport [Multimedia], Sport Tech, Sport Executive, S Sport, S Sport [Multimedia] and Luxe to a more simplified SL, SE, SE Multimedia, GT trim level line-up – makes more sense to have four trim levels.

I haven’t quite worked out what to do with the rest of the Infiniti line-up – although the QX50 would become the Skyline Crossover, like its Japanese equivalent model [its predecessor, the Infiniti EX was badged as this in Japan].

Chrysler discontinuing all models except Pacifica and becoming a mobility company under FCA.

I wouldn’t go with this strategy – I would instead have focused on Chrysler offering hatchbacks with raised ground-clearance and AWD.

The Chrysler Cirrus name would return on the Chrysler UF platform for a new raised hatchback-style crossover which would be front-wheel-drive or all-wheel-drive.

It would have edgy 1990s-esque styling and be more along the lines of a Mitsubishi ASX/Outlander Sport – car-like, hatchback design – than a Ford Edge – SUV-like macho styling.

Although the Chevrolet HHR may not have worked as a retro car, this wouldn’t be marketed as a retro model.

It would use the Jeep Grand Commander’s 2.0-liter/231hp 4-cylinder turbo engine – FCA’s GME T4 Hurricane engine – for the base models, and offer a 3.0-liter/285hp V6 Pentastar V6, along with the hybrid engine from the Pacifica minivan.

Trim level choice would be simple – LXi, LXi AWD, Highline, Highline AWD, Premium, Premium AWD, GT and GT AWD [effectively four trim levels; AWD denoting all-wheel-drive].

Although the original Chrysler Cirrus didn’t have a good reputation for reliability, this would be a reboot for a new generation who would be less familiar with the name – effectively starting from a clean slate.

This would be shown at an auto show like the Chicago or Los Angeles one as a concept car.

Ford Focus sedan

In this article it says the Focus sedan isn’t intended to sell in big volumes, but here, I would target the Focus sedan at ASEAN markets as a rival for the Toyota Corolla Altis and Honda Civic.

Currently, there is no Ford Focus ST sedan, but I would offer one with the 2.3-liter/276hp 4-cylinder gasoline engine, instead of the Focus ST hatchback, because in ASEAN markets the sedan is preferred over the hatchback [Toyota sells the Corolla solely as a sedan in many ASEAN markets, no hatchback except in Australia and New Zealand]. Toyota offered the Corolla Altis 2.0V as a sports model, but it had a 2.0-liter/147hp 4-cylinder gasoline engine, so wasn’t quite a sports sedan, despite the looks.

I know that crossovers are popular, but for those who want a cheap, basic car, the sedan is still popular with buyers who usually go for Japanese or Korean.

I would be interested to hear what you would have done differently with recent motor industry decisions.

submitted by /u/SubaruToyotaFan1986
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2001 Renault Clio 1.2 16v weird engine noise

Hello guys! I bought a 2001 clio 1.2 16v last week, and since then i’ve been noticing 3 problems. I need to change a cv axle, and the valve cover gasket that is leaking to the heatshield burning oil, And there’s the weird noise. It’s like a crackling sound, it comes from the left side of the engine and its getting worse (when i got it, it started at about 1,5k rpm the noise, and noise at 1k) and im afraid that it’s just not a annoying sound, but something serious. Here’s the videos of the sound: https://www.youtube.com/watch?v=utA6maUSNk0 https://www.youtube.com/watch?v=A1w8Zx2Jws0

Any help would be apprecitated!


submitted by /u/El_SPiNZ
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