+ Reply to Thread
Results 1 to 2 of 2

Thread: deciles

  1. #1
    Points: 5,128, Level: 45
    Level completed: 89%, Points required for next Level: 22

    Posts
    9
    Thanks
    0
    Thanked 0 Times in 0 Posts

    deciles




    Women's weights are normally distributed with a mean of 143 lb and a standard deviation of 29lb. Find the third decile, D3, which separates the bottom 30% from the top 70%.


    I tried doing the z=(y-mean)/std. deviation, but it did not work for me. We haven't done anything with these in class and I can't find any examples in my book. Please help!

  2. #2
    TS Contributor
    Points: 17,636, Level: 84
    Level completed: 58%, Points required for next Level: 214
    JohnM's Avatar
    Posts
    1,948
    Thanks
    0
    Thanked 6 Times in 5 Posts

    You need to look up the z value in the z-table, not compute it. You should be able to locate the z-value that separates the bottom 30% from the rest --> it should have a proportion of the area equal to 0.30. Hint: it will be negative.

+ Reply to Thread

           




Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts






Advertise on Talk Stats