Statistic

posted by .

You plan to conduct a political poll of people in Berkeley, asking whether people prefer apples (A) or bananas (B). You have been endowed with the ability to select people completely at random from the population of Berkeley. If you ask n randomly selected people which they prefer and calculate the fraction that prefer apples, the variance of your result will be about 0.25 / n (I am telling you this as a fact). You would like to choose n to
be large enough that your 95% confidence interval will extend about 0.03 above your
estimate (whatever it turns out to be) and about 0.03 below your estimate (if you read the newspaper, political polls are always reported with “a 3% margin of error”, and that is what I am defining). By definition, a 95% confidence interval roughly needs to extend 2 times the standard deviation from the estimated mean (in this case, the mean is the fraction that prefer apples; it turns out this will be very close to normally distributed even though the numbers are fractions and can have only discrete values). Using that rule, how many samples do you need for your 95% confidence interval to extend 0.03 above and 0.03 below the mean?

Respond to this Question

First Name
School Subject
Your Answer

Similar Questions

  1. human anatomy and physiology

    1. name and define in detail the four organic compound groups that make up the chemistry of living things. Lipids, carbohydrates, proteins, and nucleic acids. See Part IV of http://www.ucmp.berkeley.edu/people/brs/biol1a/Lect2.html …
  2. science

    one way of describing population distribution is the number of people per area, but it can also refer to a)the hybridization composition of the people b) the age distribution of the people c) the political composition of the people …
  3. statistics

    in 1995,the gallup poll asked a sample of 620 adults whether their support of baseball had been affected by a recent player strike,248 people in the sample said "yes".identify the population,parameter,sample,and statistic in this setting
  4. stats

    suppose that a population of people is 1200. .25 of the population is white. we take a random sample of 100 people. What is the probabilit that more than .29 of these people are white?
  5. Civics

    The most important effect of the amendments that have been added to the Constitution since the Civil War has been that more people are eligible to become citizens more people are involved in the political process *** more people immigrate …
  6. Math

    A Voting Poll: Candidate A: 30% Candidate B: 50% Undecided: 20% The Table above summarizes the results of an election poll in which 4000 voters participated. In the actual election, all 4000 of these people voted and those people who …
  7. algebra

    A group of 1,200 people was surveyed to find their favorite choice of fruit. the pie gives results of people surveyed oranges 19.2% kwiw 16.2% bananas16.6% apples 30.2% other 12.8% of the people surveyed, how many prefer bananas?
  8. math

    If 35% of people surveyed prefer orange to apples.Out of 475 people surveyed how many can be predicted to prefer orange
  9. Maths

    Fifty people said they liked apples or bananas or both. Forty percent of people like apples and 70% of the people like bananas. What percentage of people like only apples?
  10. Data

    Of 20 people invited to a pool party, 4 prefer vanilla ice cream, 7 prefer chocolate, and 3 prefer strawberry. The host surveys six of these people at random to determine how much ice cream to buy. a) What is the probability that at …

More Similar Questions