# Recent content by AngleWyrm

1. ### Causality and independence

katxt said: We can express this probability as P( X has had a motor accident | X is in hospital). The condition clearly happened after the event. If P( accident | hospital) > P(accident) then we have a measured judgement people who've had accidents are more frequently found in hospitals. The |...
2. ### Causality and independence

If P(cancer | smoker) > P(cancer), cancer is more frequent among smokers, then can we say smoker came before cancer, and shows a causal relationship? Here's the rub I've seen so far, which seems to me Simpson's Paradox: It may also be the case P(smoker | cancer) > P(smoker), smokers are more...
3. ### Causality and independence

Do you agree that P(A|B) is a mathematical model of dependence? That is to say P(A) given P(B) states a before/after relationship, and a causality of B effecting A?
4. ### Causality and independence

You appear to be discussing something that isn't the draw of a card A followed by the draw of a card B. It looks like you might be talking about a strategy game where two players hold more than one card each, and are choosing to play cards from their hands. Do you agree the cards a player drew...
5. ### Causality and independence

Pearson's chi squared test for independence Tests of Independence If A and B are independent then P(A AND B) = P(A)P(B)
6. ### Causality and independence

Player 1 draws a card from a deck, and then player 2 draws a card. This is a causal relationship: Player 1's draw occurred before player 2's draw, and had an effect on what player 2 could draw. The player's hands are not independent events. The claim event A did something to effect the outcome...
7. ### Testing if a sample came from a population

Yes that's a good match: Pearson's Chi squared test of independence Calculators for finding decision value, and test statistic
8. ### Testing if a sample came from a population

The stated claim is event A and event B are independent, with probabilities P(A) = 0.90 and P(B) = 0.20 Given a set of samples, how can we measure the certainty they were drawn from that population? With two events, there are four possible outcomes to a test, {A and B, A and not B, not A and B...
9. ### Creating a scale with dichotomous and continuous items

Check out Principal Component Analysis
10. ### How to test this scenario?

So you have a population of all people, and four samples drawn from that population, called red, brown, blonde, and black. Since this is a problem where sample sizes differ, we should use a z-score that takes sample size into account. Normal z score = (observation - average)/(standard...
11. ### Cross-national comparison best methodology and research questions advice

I hypothesize attitudes toward justice correlate with annual wages. Does the survey taker earn more than the median for 1 person? More than ten people? Less than 1/5th?
12. ### Chance performance in a binary response task

80/100 = 4/5 of answers are true, 1/5 of answers are false. If the subject knows this, then their best guessing strategy is to guess true 4/5 of the time and false 1/5 of the time.
13. ### A coincidence isn't that unlikely?

Gambler's Fallacy
14. ### A coincidence isn't that unlikely?

The Gambler's Fallacy is a trick of memory, where the observer considers what has been observed but doesn't remember what hasn't taken place.
15. ### Question Regarding Standard Deviation of Rate Vs. Time

Mean for the rate in ml/s wasn't calculated in the original, so I madea copy and added it (blue outlined cells) I also agree the time to complete the fill operation is a better measure. The average speed in ml/sec varies considerably between pumps, and so a small variance in the smallest...