I am working on a review sheet and got everything except for this one. I am not sure whether to use z or t.

The number of hours per week that high school juniors watch TV is normally distributed with a mean of 8 hours and a standard deviation of 2 hours. If 100 students are chosen at random, find the probability that the mean for that sample is between 8.2 and 8.8.
a. 1598 b. .1586 c. .1156 d. .1152

Note: standard deviation/ the square root of n.
Check out the Central Limit Theorem

  1. 👍 0
  2. 👎 0
  3. 👁 56
asked by Joe
  1. Use z-scores.

    For this problem:
    z = (x - mean)/(sd/√n)

    With your data:
    z = (8.2 - 8)/(2/√100) = 1.00
    z = (8.8 - 8)/(2/√100) = 4.00

    Answer: .1586 is the probability (check a z-table between z = 1.00 and z = 4.00)

    1. 👍 0
    2. 👎 0
  2. Thanks!! That really helped. I had the steps you had, but was stuck on z vs t.

    1. 👍 0
    2. 👎 0
    posted by Joe

Respond to this Question

First Name

Your Response

Similar Questions

  1. Introduction to Graphic Design A

    Hello! Thanks for checking my question out! ____ Last semester's geology class worked together to create a review sheet for the final exam. The review sheet contains information that covers 13 chapters worth of content along with

    asked by Da Fash on September 18, 2017
  2. Electrical versus Gravitational Forces (Physics)

    Multiple Choice help: * _____ forces between charges are enormous in comparison to ______ forces. * A. electrical, gravitational (possible?) B. gravitational, electrical (possible?) C. positive, negative (wrong, I think) D.

    asked by Angela on February 25, 2011
  3. Grammar and Composition

    Hi, I have started working on the Phone Book Character essay again. i did the drafting sheet just now. I will try to do as much of the essay as i can, while ofcourse still asking questions from you guys when i need help, but

    asked by y912f on November 4, 2009
  4. Algebra

    A sheet metal fabricator makes boxes from sheet of steel. Each sheet of steel has an area of 1500cm2. 6cm squares are cut from each corner and the edges are bent up to form a box with a volume of 3456cm3.What are the dimensions of

    asked by Emily on November 24, 2017
  5. math

    6cm diameter discs are cut from a sheet 130cm long and 70cm wide.(a)How many discs can be cut in this way (b) what area of the sheet is wasted? (My working so far). Area of rectangle=L*B 130*70=9100cm^2 area of circle=22/7

    asked by james on April 30, 2015
  6. french

    i need a review sheet for grade 7 french... the units were: la meteo, la famille and le ecole

    asked by Anonymous on June 9, 2008
  7. Maths

    A rectangualr metal sheet is 32m long, 16m wide and 12mm thick. Eight circular holes, each of diameter 3m are cut in the sheet, so that none of the holes overlap. Calculate the volume of metal remaining, correct to 3 decimal

    asked by Jiskhaa on January 15, 2012
  8. Calc Help

    q=(1000/p+1)^2 - 1 find q' Please help. Question on review sheet. I will be glad to help you, or critique your work. What do you think the way to solve it is>

    asked by Evan on May 1, 2007
  9. algebra

    2x+(x-y)^3 when x=9 and y=7 This problem is from a test review sheet (answer included)I have almost filled a notebook trying to solve this.

    asked by Vikki on February 9, 2011
  10. Science

    Which are reasons to get a claim peer reviewed? Check all that apply. A peer review verifies conclusions. A peer review proves everyone else wrong. A peer review maintains standards of the field. A peer review identifies sources

    asked by Alexis on September 13, 2015

More Similar Questions