5 ms·

I'm not a statistician, but the results section is worth reading -- the fructan results are not much higher than placebo but both placebo and fructan are more a

I'm not a statistician, but the results section is worth reading -- the fructan results are not much higher than placebo but both placebo and fructan are more affective than gluten. "Overall GSRS-IBS scores differed significantly during gluten, fructan, and placebo challenges; mean values were 33.1±13.3, 38.6±12.3, and 34.3±13.9, respectively (P = .04). Mean scores for GSRS bloating were 9.3±3.5, 11.6±3.5, and 10.1±3.7, respectively, during the gluten, fructan, and placebo challenges (P = .004). The overall GSRS-IBS score for participants consuming fructans was significantly higher than for participants consuming gluten (P = .049), as was the GSRS bloating score (P = .003). Thirteen participants had the highest overall GSRS-IBS score after consuming gluten, 24 had the highest score after consuming fructan, and 22 had the highest score after consuming placebo. There was no difference in GSRS-IBS scores between gluten and placebo groups."

ezzaf 9y ago
This was my thoughts too. The values appear to be fairly similar for all three, especially given the large variations. Not to mention that they're explicitly trialling this with people "for whom celiac disease had been excluded". So an alternate conclusion could be "people without celiac disease but with self reported gut issues don't respond significantly differently to fructan, gluten, and placebo". Which is... not surprising?
- ameister14 9y ago
  They don't appear that similar to me - if you plot them graphically you'll see a significant difference, particularly at the lower end.
  - karlkatzke 9y ago
    P values of less than .005 generally mean that you accept the null hypothesis. The authors did otherwise for one hypothesis, which I find interesting.
    - alexandercrohde 9y ago
      You're wrong on two accounts. You want a low p-value, the lower the p-value the stronger the evidence. A p-value is cutoff traditionally at .05 (1 in 20), and if it's p < .05 you can reject the null hypothesis. The "null hypothesis" is the OPPOSITE of your paper's hypothesis (so you want to reject it): the null hypothesis is "All the variation we saw was from chance"
      - nonbel 9y ago
        Why not make the null hypothesis the same as your paper's hypothesis? Wouldn't that make more sense?
        themadryaner 9y ago
        You cannot prove the null hypothesis; you can only disprove it. The p-value is the probability that the null hypothesis is true. So if the null hypothesis is that there is no difference, and there is a low probability of that being true, then you have shown that there is a difference between the groups. If the p-value is high, you do not show that the null hypothesis is true. Instead, you show that you did not find a statistically significant difference. This can happen when the difference between the values is small or there is not enough data to make the difference clear, which is why a high p-value is not enough to reject the alternative hypothesis.
        jostylr 9y ago
        > The p-value is the probability that the null hypothesis is true. No, the p-value is the probability that the given data generated is as far away or farther by random chance given the null hypothesis is true. That is to say, we assume the null hypothesis to make some predictions and see if the data is a likely occurrence under those assumptions. This is not the same as the probability that the null hypothesis is true. If that is what you want (and most of us do want this), then Bayesian methods are more appropriate though they are more complicated and more sensitive to initial assumptions.
        9y ago
CodeWriter23 9y ago
My thought is they aren’t looking at anything other than gluten and fructan. I’m sure there are other compounds common in foods containing gluten that need to be examined and eliminated as causative before publishing a study with a title that implies a conclusion.
goialoq 9y ago
if placebo is a sugar pill, maybe it's a sugar sensitivity...
- brbsix 9y ago
  I assume placebo is the same muesli bar used in the other groups (without the supplemented fructan or gluten).
  - basicplus2 9y ago
    Ah! Excellent point!
- lazyasciiart 9y ago
  if the placebo is a sugar pill then it's an experimental methods failure.

ezzaf 9y ago

This was my thoughts too. The values appear to be fairly similar for all three, especially given the large variations. Not to mention that they're explicitly trialling this with people "for whom celiac disease had been excluded". So an alternate conclusion could be "people without celiac disease but with self reported gut issues don't respond significantly differently to fructan, gluten, and placebo". Which is... not surprising?

ameister14 9y ago
They don't appear that similar to me - if you plot them graphically you'll see a significant difference, particularly at the lower end.
- karlkatzke 9y ago
  P values of less than .005 generally mean that you accept the null hypothesis. The authors did otherwise for one hypothesis, which I find interesting.
  - alexandercrohde 9y ago
    You're wrong on two accounts. You want a low p-value, the lower the p-value the stronger the evidence. A p-value is cutoff traditionally at .05 (1 in 20), and if it's p < .05 you can reject the null hypothesis. The "null hypothesis" is the OPPOSITE of your paper's hypothesis (so you want to reject it): the null hypothesis is "All the variation we saw was from chance"
    - nonbel 9y ago
      Why not make the null hypothesis the same as your paper's hypothesis? Wouldn't that make more sense?
      - themadryaner 9y ago
        You cannot prove the null hypothesis; you can only disprove it. The p-value is the probability that the null hypothesis is true. So if the null hypothesis is that there is no difference, and there is a low probability of that being true, then you have shown that there is a difference between the groups. If the p-value is high, you do not show that the null hypothesis is true. Instead, you show that you did not find a statistically significant difference. This can happen when the difference between the values is small or there is not enough data to make the difference clear, which is why a high p-value is not enough to reject the alternative hypothesis.
        jostylr 9y ago
        > The p-value is the probability that the null hypothesis is true. No, the p-value is the probability that the given data generated is as far away or farther by random chance given the null hypothesis is true. That is to say, we assume the null hypothesis to make some predictions and see if the data is a likely occurrence under those assumptions. This is not the same as the probability that the null hypothesis is true. If that is what you want (and most of us do want this), then Bayesian methods are more appropriate though they are more complicated and more sensitive to initial assumptions.
        9y ago

CodeWriter23 9y ago

My thought is they aren’t looking at anything other than gluten and fructan. I’m sure there are other compounds common in foods containing gluten that need to be examined and eliminated as causative before publishing a study with a title that implies a conclusion.

goialoq 9y ago

if placebo is a sugar pill, maybe it's a sugar sensitivity...

brbsix 9y ago
I assume placebo is the same muesli bar used in the other groups (without the supplemented fructan or gluten).
- basicplus2 9y ago
  Ah! Excellent point!
lazyasciiart 9y ago
if the placebo is a sugar pill then it's an experimental methods failure.