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How consistent are our stars: a statistical analysis

Discussion in 'Houston Rockets: Game Action & Roster Moves' started by MFW2310, Apr 2, 2005.

  1. MadMax

    MadMax Contributing Member

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    exactly right. all of this seems to be coming back to shooting percentage. i think we should all expect a guy who is 7'6" and playing close to the basket to have a higher shooting percentage than a guy who plays the perimeter. that's blatantly obvious to me.

    but this is not what is meant if your'e trying to counter the notion that Yao is inconsistent. i don't think that's what his critics mean at all.
     
  2. tigermission1

    tigermission1 Contributing Member

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    MFW...

    Can you tell me the ppg averages month-by-month for both Yao AND T-Mac, up to the month of March?

    The reason is that the ppg averages for both players have evolved since the beginning of the season, so I am not sure if that affects the "above average/below average" performances analysis, because these averages have changed and evolved as the season has evolved.

    I don't know if that would affect your analysis or not.
     
  3. bfunw

    bfunw Contributing Member

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    Then after learning that Yao was injured in Suns game (March 11),
    according to Houston Chronic, how do you think about all the critics we heard in Clutch BBS?
     
  4. tigermission1

    tigermission1 Contributing Member

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    LOL!

    Yah, that is the excitement part of the watching NBA basketball, if Yao or T-Mac were dead-on to their averages every game, it would be deathly boring to watch the games.

    so in that sense, HAIL INCONSISTENCY!:D
     
  5. bfunw

    bfunw Contributing Member

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    That's why we go/watch games, after all. We expect UNEXPECTED!

    However those lousy losses make fans depressed everywhere. So ... calm down, look forward, and expect UNEXPECTED.
     
  6. MFW2310

    MFW2310 Contributing Member

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    Here are the monthly results. I included last night's game in March because we don't have sufficient April stats.

    Yao Tmac
    PPG RPG APG PPG RPG APG
    Nov 17.875 7.625 1.125 20.21428571 5.142857143 5.428571429
    SD 9.401241053 2.986078811 1.310216267 6.053334382 3.009143575 2.901307019

    Dec 19.84615385 10.07692308 0.615384615 27.71428571 7.285714286 5.642857143
    SD 7.625026271 3.774068063 0.767947648 9.666982438 2.672612419 2.273835893

    Jan 17.3125 8.125 0.4375 28.06666667 6.466666667 5.933333333
    SD 5.747100718 2.526525942 0.62915287 6.787242936 2.166849809 2.548575699

    Feb 20.3 7.5 1 24.9 5.4 7.2
    SD 5.578729445 3.274480451 0.942809042 8.238797107 3.025814858 2.250925735

    March 16.875 7.9375 0.6875 25.58823529 6.117647059 4.588235294
    SD 5.389805191 4.739461995 0.793200269 9.943960626 2.619216317 1.839117435

    Notice once again that Yao's SD is lower, and much lower progressively than TMac. If anything (putting my stat w**** hat on), Yao has been becoming more "consistent" in terms of deviation from the mean (in the sense that you'd more confidently predict what he's gonna get any given night than TMac) as the season progressed and TMac has been becoming more inconsistent. TMac's performance also appears to have tapered off after his hot Dec and Jan months.

     
  7. MFW2310

    MFW2310 Contributing Member

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    Ugh, formating:
    Yao:
    Nov
    17.875, SD 9.401241053

    Dec
    19.84615385, SD 7.625026271

    Jan
    17.3125, SD 5.747100718

    Feb
    20.3, SD 5.578729445

    March
    16.875, SD 5.389805191

    TMac:
    Nov
    20.21428571, SD 6.053334382

    Dec
    27.71428571, SD 9.666982438

    Jan
    28.06666667, SD 6.787242936

    Feb
    24.9, SD 8.238797107

    March
    25.58823529, SD 9.943960626

    Once again, you see that Yao won't signficantly vary from the mean. At worst he'll get 16.9 (feel free to round off) for this season. At best he'll get 20.3.

    TMac will get anywhere from 20.2 to 28.1. So once again, I don't know what consistency means, basketball wise.
     
  8. KaiSeR SoZe

    KaiSeR SoZe Contributing Member

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  9. hotballa

    hotballa Contributing Member

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    ok so both are inconsistent,. but TMac's inconsistency ranges from 25 points to 45 points, while Yao ranges from 5 to 25, and lets not even talk about his rebounding
     
  10. NewYorker

    NewYorker Ghost of Clutch Fans

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    I would bet good money that the last time Yao and T-mac played together barring injury or ejections and scored less then 13 points was NEVER.

    How's that for debunking your results?

    T-Mac is far more consistant. No his jump shot may not fall with all that much consistancy, but his overall play is.

     
  11. MFW2310

    MFW2310 Contributing Member

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    You didn't debunk nothing. Like I said in the disclaimer, "People with ulterior motives lie with stats and people who don't understand them gets fooled by them." There are always those few people who tell us that stats are useless, because they don't understand them.

    What the stats told me is AT MOST 2.5% of all games, Yao and TMac would combine for under 13 points, as the 95% CI indicates. Which means that if both play together for 1000 games in their career, they would have AT MOST 50 games in which they score under that. Quite often, the actual % is even higher than 95%. It is often, say... 99%, maybe higher. And it is possible that the sample size was just too small. But what I'm telling you here is that (based on those stats), the WORST Yao and TMac could possibly do is score 13 points or under 2.5% of the time.

    You notice I said, here are the stats, draw your own conclusions. I understand stats aren't perfect, however, it is the best we have available. But why do that right? Why make observations and try to draw conclusions when you can come up with the conclusion and try to make observations fit that? Actually on second thought, you didn't even bother to manipulate the facts. You just said something as if it's absolutely true. :rolleyes:

    EDIT: Changed 5% to 2.5%
     
    #31 MFW2310, Apr 2, 2005
    Last edited: Apr 2, 2005
  12. Tango

    Tango Contributing Member

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    The only thing that this debunks is your understanding of statistics :).

    The 95% confidence interval means there's only a 2.5% chance that T-MAC & Yao combine for 13 pts or less in a game. That's some pretty good odds meaning that we should be pretty confident that they will never combine for 13 pts or less.
     
  13. Tango

    Tango Contributing Member

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    Ah, too slow in my response. MFW - remember it's 2.5% above and 2.5% below = 5% total on the outside of your ranges.
     
  14. MFW2310

    MFW2310 Contributing Member

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    Um no. Yao points ranges from 4.4 to 32.1. TMac's points range from 8.2 to 42.5, although TMac is more "consistent" rebounding wise.

    I also love how people get all defensive something unexpected come up about their fav star. Notice I didn't say Yao sucks because xyz, TMac sucks because of xyz. I just gave the stats and said draw your own conclusions.

    Yet we have people like you bashing one in favour of the other. I guess this proves that there are YOFs and TOF, etc more than anything else, despite that fact that trying to explain their consistency was my original purpose. And here I thought they played for the same team...
     
  15. MFW2310

    MFW2310 Contributing Member

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    You are right. My bad. Trying to eat pizza, watch TV, talk to the gf and post at the same time. Sorry. The worst Yao and TMac can do is score 13 points and under 2.5 % of the time.
     
  16. NewYorker

    NewYorker Ghost of Clutch Fans

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    Actually it's much less, as your statistical analysis is quite naive and full of false assumptions.

    First of all, you're assuming that T-macs play and Yao's play are mutually exclusive - which clearly it's not.

    Second of all, both players would have the have their worst night ON THE SAME NIGHT - a very low probability.

    You're analysis states this would occur 1 in every 20 games. Take a look at the data - it's never happened this season.

    In fact, you could do the same analysis with any two teammates and find out that their two worst nights occur far less then 1 in 20. You can't just add the lower bounds and assume it's still a 95% confidence interval.

    It's not as simplistic as you're making it out to be. Just because you have some numbers and it seems like you're doing something logical doesn't necessarily mean that...the world is full of people with B.S. stat knowledge who try to force a mathematical intrepretation on something they don't fully understand.

     
  17. MFW2310

    MFW2310 Contributing Member

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    First of all, as Tango pointed out, I made a stupid mistake. At worst they'll do is score under 13 points 2.5% of the time. The other 2.5% is when they'll combine for over 75.

    Secondly, like I said, it is the WORST case scenario. Maybe Yao and TMac have one off game 0.1% chance, meaning a chance of 1 in 2000 games. 95% CI isn't meant to explain the exact point, which is impossible to determine. It is meant to give you a range.

    Finally, I didn't say either way about them playing either together or in isolation. However, if there is anything that would affect how they play together, it would likely to have been already been included in the stats. This is because that they are already playing together. Their stats already reflect what they do together, as supposed to independently.
     
    #37 MFW2310, Apr 2, 2005
    Last edited: Apr 2, 2005
  18. Tango

    Tango Contributing Member

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    You're correct the variables not being mutually exclusive. However MFW's premise of the comparative statistical variation between T-MAC and Yao is correct. If you're saying his statistical premise is incorrect then perhaps you should try to disprove with some deductive reasoning which you haven't done yet.
     
  19. NewYorker

    NewYorker Ghost of Clutch Fans

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    Let's assume that T-Mac and Yao's play are mutually exclusive.

    Then, what was it, Yao's lower bound was 5 points and T-macs 7 points? And since it's a normal distribution two-tailed, then there's a 2.5% chance that in any given night they will score below their lower bounds.

    Since 2.5% = 1 in 40...


    The chance that both will both score below their lower bounds (less then 12 pts or whatever) is...

    1/40 * 1/40 = 1/1600 or 0.06%

    They would have to play an average of 1,600 games before it happens once.

    Therefore, I'm 99.94% sure that they won't score less then 12pts in a game combined....a lot higher then the 97.5% you're claiming.
     
  20. snowmt01

    snowmt01 Contributing Member

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    Actually 2.5% is still not correct.

    The probabablity for Yao and Tmac combined to get less
    than 13 can be obtained by enumeration.

    P(Yao = 0, Tmac = 12 and vice versa)
    +
    P(Yao = 1, Tmac = 11 and vice versa)
    +
    ...
    +
    P(Yao = 6, Tmac = 6)



    P(Yao < 4.2, Tmac < 8.4) is only part of the story, and that
    probability is way lower than 2.5%.

    Assuming their scores are mutually independent
    The joint probability
    P(Yao < 4.4, Tmac < 8.2) = P (Yao < 4.2) x P(Tmac < 8.4)
    = 2.5% x 2.5% = 0.0625%

    Sorry to make it too academic ;)
     

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