1. Not finding help here? Sign up for a free 30min tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

1st year stats, empirical rule- range of values

  1. Jan 26, 2006 #1
    Hello
    I am taking 1st year stats at university, and I have lab questions I am supposed to answer. I am VERY confused.
    My data set is:
    53, 33, 25, 63,26, 64, 32, 21, 45, 64, 38
    I calculated the mean:42.182
    the sample variance:272.147
    The range:43
    The percentile rank of the data value 45: 59th
    The value corresponding to the 80th percentile:63
    Q1:26
    Q2:38
    Q3:63
    Outliers: none
    Standard deviation: 16.497
    Now I am asked: according to the empirical rule, if the above data is normal find the range of values in which approximately 68% of the data will lie. I know the empirical rule applies only to bellcurved graphs... but this would not produce a bell curve correct? So would there be an answer?

    Then they ask: What is the actual percentage of the data that lie in your interval from above.?

    Any help is appreciated thanks!
     
  2. jcsd
  3. Jan 26, 2006 #2

    0rthodontist

    User Avatar
    Science Advisor

    You should know that if the data is normal then about 68% of the data lies within 1 standard deviation of the mean. They expect an incorrect answer for the first part--they are saying, what if it were normal, then what would the answer be.
     
  4. Jan 26, 2006 #3
    THANKS! I realize now what they are asking and got the answer:

    mean-standard deviation=25.685
    mean+standard deviation= 58.679

    So for the next part: What is the actual percentage of the data that lies in the intervals from previous question.

    So would I do, which of these intervals: 22 25 26 32 33 38 45 53 63 64 64 will lie between 25.685 and 58.679??
    which is 26, 32, 33, 38, 45, 53
    so: 6/11 fall within those intervals, so 6/11 * 100 = 54.54% of the data lie between these intervals.
    THANKS again.
     
  5. Jan 26, 2006 #4

    0rthodontist

    User Avatar
    Science Advisor

    Yes, that's correct.
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?



Similar Discussions: 1st year stats, empirical rule- range of values
  1. Range of values (Replies: 8)

Loading...