normal approximation

  1. C

    P charts based on binomial distribution - Statistical Process Control

    Hello all, I have a question related to the use of p-chart in a process where there are defect rates measured. The control limits for this type of chart is calculated with +/- 3 sigmas around the mean (with mean = np and sd = sqrt(n*(1-p)*p)) As it is using i +/- 3 sigmas it assumes that we...
  2. F

    Plotting a normal distribution curve over a histogram

    I'm trying to plot a normal distribution curve over my histogram but I can't get my code to work for the curve. It just looks like it's plotting a very low curve, what am I doing wrong? This is my code: minutes<-c(107, 116, 127, 126, 111, 90, 125, 124, 92, 121, 131, 137, 95, 101, 101, 111...
  3. D

    Normal Approximation questions. Finding p?

    1) An ESP test involves five shapes (star, square, circle, wave, cross) on cards. We record 1000 attempts. (a) What is the probability that a subject without ESP will be successful in at least 24% of the attempts?(b) The researcher considers evidence of ESP to a proportion of successes so large...
  4. D

    Normal Approximation probability question

    Consider a four-sided die loaded so that 1 shows 40% of the time. If we roll this die 50,1000,2000,4000,8000 times, find the probability in each case that at least 42% of the rolls are 1's Can you please help me understand how to calculate the italicized part of the answer? Answer: P =...
  5. D

    Normal Approximation question

    1) A fair coin is tossed 600 times. What is the probability that the number of heads will be between 290 and 310? (I have the answer, but I need help with the calculations of certain parts of the answer) Answer: p = 0.5, n = 600 ---------> I don't know how to calculate p mean...