Intro to probability

posted by .

Two balanced coins are tossed. What are the expected value and the variance of the number of heads observed?
I'm confused on how to start. I don't know how many times im suppose to toss coin, and how to set up my table for the expected value and then find variance, I know how to find expected value when I know how to use what's given to me, hope you can help. I feel that the answer is probably simple but i'm stuck on info i think it lacks.

  • Intro to probability -

    p = 1/2 for heads or tails

    this is a binomial distribution

    mean = n p = n/2

    variance = n p (1-p) = n/4

    It is indeed lacking n so has to be answered that way

  • Intro to probability -

    Wait a minute, they said two coins. Assume each tossed once. n = 2

  • Intro to probability -

    thanks damon for your help

Respond to this Question

First Name
School Subject
Your Answer

Similar Questions

  1. math

    a fair coin is tossed in the air 4 times. if the coin lands heads up the first three tosses, what is the probability the coin will land heads up the fourth toss?
  2. math answer check

    Three coins are tossed, and the number of heads observed is recorded. (Give your answers as fractions.) (a) Find the probability for 0 heads. Incorrect: Your answer is incorrect. . Your answer cannot be understood or graded. More Information …
  3. algebra

    A coin is tossed 3 times. Find the probability of obtaining the following: a) heads on the first and last toss, and tails on the other toss b) at least 2 heads c) at most 2 heads
  4. math

    A balanced coin is tossed 12 times and heads appears each time. What is the probability that tails will appear on the next toss?
  5. Data Management

    A random variable X is defined as the number of heads observed when a coin is tossed 4 times. Make a chart that shows the probability distribution for X. What is the expected value?
  6. Probability

    A defective coin minting machine produces coins whose probability of Heads is a random variable Q with PDF fQ(q)={3q2,0,if q∈[0,1],otherwise. A coin produced by this machine is tossed repeatedly, with successive tosses assumed …
  7. statistics

    Five coins all balanced the same were tossed 150 times. Note that, while the coins are all balanced the same, they may or may not be fair coins. Since five coins were tossed, the possible number of heads for each toss could be zero …
  8. math

    A balanced coin is tossed 12 times and heads appears each time. What is the probability that tails will appear on the next toss?
  9. probability

    Tossing a pair of coins We have a white coin, for which P(Heads)=0.4 and a black coin for which P(Heads)=0.6. The flips of the same or of different coins are independent. For each of the following situations, determine whether the …
  10. probability

    Adefective coin minting machineproducescoinswhoseprobability ofheadsisarandomvariable P with PDF 1+sin(2πp), if p ∈ [0,1],fP (p)= 0, otherwise. Inessence,aspecificcoinproducedby thismachinewillhavea fixedprobability P = …

More Similar Questions