Statistics

) In a rural area, the infected rate of certain disease is 0.20 (i.e., 20%). A sample of 20 people is taken from the area - selections are independent. Define X as the number of people in the sample who are infected by the disease.

(1) This X is a binomial variable. What are the parameter values of this distribution? What are the mean value and standard deviation of X?
Ans.




(2) What is the probability that at least 4 of the 20 people are infected? Use Binomial table.
Ans.




(3) Compute P(X  4) using normal approximation and Poisson approximation, respectively.
Ans.

Normal approximation:





Poisson approximation:






(4) Are those in (3) good approximations? Why?
Ans.

  1. 👍 0
  2. 👎 0
  3. 👁 73
asked by Trell

Respond to this Question

First Name

Your Response

Similar Questions

  1. Epidemiology

    Can some one please check this for me. I am not sure if I am on the right track. Complete the problem below. Disease X is one that often results in severe illness, but never is fatal. On March 21, 1990, 30 students developed

    asked by DANIELLE on May 4, 2008
  2. Math

    Scientists are researching a contagious disease. They found that, on average, each person who is infected transmits the disease to 0.03 other people within one year. Currently, there are 3,000 infected people in the country. Use

    asked by Luke on September 27, 2010
  3. Algebra

    A contagious disease is infecting residents of a town of 7,300 residents. The number of residents infected t days after the disease has begun is given by the function f(t)=(7300)/1+500e^-0.5 t How many residents are infected with

    asked by Laurie on August 2, 2009
  4. algebra

    A contagious disease is infecting residents of a town of 7,300 residents. The number of residents infected t days after the disease has begun is given by the function f(t)= 7300/1+500e-0.5t How many residents are infected with the

    asked by joyce on November 21, 2010
  5. Math

    Annie learned that on day 1 of the outbreak, there were 105 infected dogs, and on day 2, there were 120 infected dogs. She noticed that each day, 15 more dogs became infected. Annie used these numbers to set up an alternative

    asked by Stacy on November 6, 2017
  6. history

    i need to invent a terrible disease myself that has been detected in another part of the world .. the people are unhappy because the government are not helping them to treat the disease..please help me find a terrible disease but

    asked by sheromeya on November 20, 2006
  7. Math

    #5. If a rancher has one cow with a contagious disease in a herd of 1000, then the time in days “t” for “n” of the cows to become infected is modelled by: t= -5ln((1000-n)/999n where “ln()” stands for natural logarithm

    asked by Sam on January 18, 2013
  8. algebra 3

    . A physician made a survey of the roundworm infection of a rural region in Hubei province in 1999. There were 68 infected among the 350 randomly sampled males, and 36 infected among the 250 females. (1). Please make a statistical

    asked by alfateh on December 25, 2014
  9. Math :)

    1.Try to solve this problem without using a formula. Suppose a disease is transmitted from an individual to one other during the period of a week. Each of those two gives the disease to two more people in the second week, so that

    asked by Kim on December 2, 2013
  10. Pre-Calculus

    On a campus of 9000 students, a single student returned to campus with a case of measles on Monday January 5th. The infirmary is keeping track of the number of students who have been diagnosed with the disease Day # of students

    asked by Guadalupe on February 10, 2015

More Similar Questions