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  1. R

    Numbers of double-headed, double-tailed, and normal coins based on one toss per coin

    Suppose I have a large jar of evenly weighted coins. I know that some of the coins are double-headed, some of them are double-tailed, and some of them are normal, but I've no idea how many. I draw 100 coins at random and toss each coin once, throwing 90 heads and 10 tails. What can be said about...
  2. R

    Calculating the probability that survey responses are arbitrary

    I have a set of 200 responses to a Yes/No survey question: 160 Yes; 40 No. Any number of the responses (between 0 and 200) could be honest and truthful, and the rest will be arbitrary. Is there any way to calculate the probability that all the No responses are arbitrary? Does the question even...
  3. R

    Probability of throwing n different numbers in m throws of a dice

    Folks I know how to calculate the probability of throwing the same number in every throw of a dice (die, if you prefer!), and I know how to calculate the probability of throwing a different number in each throw of a dice. But how do I calculate the probability of throwing n different numbers...
  4. R

    Calculation of expected values for chi-squared test

    Folks I need to work out the probability that a set of survey results occurred by chance, and I intend to use a chi-squared test. However, I haven't studied mathematics formally since I was 16, and I need someone to confirm whether my calculations of expected values are accurate and, if not...