statistics

Professor Smith conducted a class exercise in which students ran a computer program to generate random samples from a population that had a mean of 50 and a standard deviation of 9mm. Each of Smith's students took a random sample of size n and calculated the sample mean. Smith found that about 68% of the students had sample means between 48.5 and 51.5 mm. What was n? ( assume that n is large enogh that the Central Limiot Theorem is applicable)

  1. 👍 0
  2. 👎 0
  3. 👁 501
asked by lauren
  1. The standard deviation of n-sample means is sigma/sqrt(n). In your case sigma = 9 for the single-sample distribution and the 1.5 for the groups of n. Therefore
    1.5 = 9/sqrt(n)
    sqrt n = 9/1.5 = 6 and n = 36

    1. 👍 0
    2. 👎 0
    posted by drwls

Respond to this Question

First Name

Your Response

Similar Questions

  1. Statistics

    Which Professor? Suppose Professor Alpha and Professor Omega each teach Introductory Biology. You need to Decide which professor to take the class from and have just completed your introductory statistics course. Records obtained

    asked by Keonn'a on February 19, 2018
  2. statistics

    Professor Smith gave a final exam in her history class. The scores on the final exam are normally distributed with a mean of 75 and a standard deviation of 6. If Professor Smith wishes to give A’s to the top 4%, what would be

    asked by Sally on April 14, 2014
  3. Stats

    I ran this an an independent samples t-test. It is a t rest according to the professor, just want to make sure I have the right one. A researcher wanted to answer the following question: What is the difference in students'

    asked by Help Please on July 14, 2012
  4. C++

    class professor {}; class teacher : public virtual professor {}; class researcher : public virtual professor {}; class myprofessor : public teacher, public researcher {}; Referring to the sample code above, if an object of class

    asked by Jason on July 25, 2007
  5. statistics

    3 PROFESSORS WANT TO KNOW IF HAVING 500 STUDENTS IN THEIR CLASS IS DETRIMENTAL TO PROPER LEARNING. 1ST PROFFESSOR RANDOMLY HANDS OUT THE QUESTIONNAIRE TO 50 STUDENTS; ALL 50 ARE RETURNED TO HIM DURING CLASS. 2ND PROFFESSOR HANDS

    asked by jane on February 12, 2008
  6. Math

    Find the probability of the following if there are 30 students in the class who have been numbered and you use a calculator to generate random numbers between 1 and 30. A number less than 10.

    asked by Mike on June 28, 2011
  7. Statistics

    In Professor Smith's statistics course, the correlation between students' total scores before the final exam and their final exam scores is r = 0.67. The pre-exam totals for all students in the course have a mean of 275 and a

    asked by Jannel on February 1, 2009
  8. Statistics

    Suppose 52 of the students in class have a calculator and 14 have a computer. It is known that 4 do not have either a computer or calc and there are 64 students in the class. Find the probability that a randomly chosen student has

    asked by Kim on May 26, 2009
  9. math

    A professor knows that in her class 37% of the students have passed an Algebra course, 29% have passed an English course, and 21% have passed both courses. If one student is selected at random from this class, find the probability

    asked by Confused on April 24, 2011
  10. Computer

    After writing the program of Exercise 17.7, write a simple program to create some test data for checking out the program. Use the following sample account data: Master file Account number Name Balance 100 Alan Jones 348.17 300

    asked by Gaurav on April 20, 2011

More Similar Questions