Mean and standard deviation

markmark
edited June 6 in Assignments

(5 pts)

Let's use our login name to generate some random data. Specifically, we'll use the position of the letters from our login name in the alphabet to generate a sequence of numbers. We'll then compute the mean and standard deviation of that data.

For example, my login name is mark and the positions of those letters in the alphabet are

m a r k
13 1 18 11

The task is to compute the mean and standard deviation of that list of numbers. Recall that, when we compute standard deviation, we always mean the sample standard deviation, rather than the population standard deviation - unless specified otherwise. Thus we divide by an $n-1$, rather than an $n$ in our formula.

Thus, my mean is %(13+1+18+11)/4 = 43/4 = 10.75%. So my standard deviation is

%sqrt(( (13-10.75)^2 + (1-10.75)^2 + (18-10.75)^2 + (11-10.75)^2)/(4-1)).%

Input like so:

%sqrt(( (13-10.75)^2 + (1-10.75)^2 + (18-10.75)^2 + (11-10.75)^2)/(4-1)).%

Comments

  • sarahsarah
    edited June 6
    s a r a h
    19 1 18 1 8

    mean: %(19+1+18+1+8)/5 = 47/5 = 9.4%

    std dev: %sqrt(((19-9.4)^2+(1-9.4)^2+(18-9.4)^2+(8-9.4)^2)/(5-1)) = 8.79%

    mark
  • isabelisabel
    edited June 6
    i s a b e l
    9 19 1 2 5 12

    mean= %(1+19+1+2+5+12)/6=8%
    standard deviation= %sqrt(((9-8)^2+(19-8)^2+(1-8)^2+(2-8)^2+(5-8)^2+(12-8)^2)/(6-1))=6.812%

    mark
  • alexalex
    edited June 6
    a l e x
    1 12 5 24

    Mean: %(1+12+5+24)/4=10.5%

    Standard Dev:
    Variance= %((1-10.5)^2+(12-10.5)^2+(5-10.5)^2+(24-10.5)^2)/(4-1)=101.667%
    Square Root= 10.083 (Standard Dev)

    mark
  • ashleyashley
    edited June 6
    A S H L E Y
    1 19 8 12 5 25

    Mean= % (1+19+8+12+5+25)/6%= 11.67

    Standard Deviation= % sqrt(( (1-11.67)^2 +(19-11.67)^2+(8-11.67) ^2+(12-11.67)^2+(5-11.67)^2+(25-11.67)^2)/(6-1)% =8.98

    mark
  • lillianlillian
    edited June 6
    l i l l y
    12 8 12 12 25

    My mean is:
    %(12+8+12+12+25)/(5) = 13.8.%

    My standard deviation is:
    %sqrt(( (12-13.8)^2 + (8-13.8)^2 + (12-13.8)^2 + (12-13.8)^2 + (25-13.8)^2)/(5-1)).%

    mark
  • jordanjordan
    edited June 6
    j o r d a n
    10 15 18 4 1 14

    mean: %(10+15+18+4+1+14)/6=62/6=10.33%

    standard deviation: %sqrt(( (10-10.33)^2 + (15-10.33)^2 + (18-10.33)^2 + (4-10.33)^2 + (1-10.33)^2 + (14-10.33)^2)/(6-1)).%

    mark
  • BeauBeau
    edited June 6
    B e a u
    2 5 1 21

    My mean is:
    %(2+5+1+21)/4=7.25.%

    My standard deviation is:
    %sqrt(((2-7.25)^2+(5-7.25)^2+(1-7.25)^2+(21-7.25)^2)/(4-1)).%

    mark
  • zachzach
    edited June 6
    z a c h
    26 1 3 8

    My mean is %(26+1+3+8)/4 = 38/4 = 9.5%

    So my standard deviation is
    %sqrt(( (26-9.5)^2 + (1-9.5)^2 + (3-9.5)^2 + (8-9.5)^2)/(4-1))%

    mark
  • benben
    edited June 7

    b e n
    2 5 14

    Mean = (2+5+14)/3= 7

    SD = %sqrt(( (2-7)^2 + (5-7)^2 + (14-7)^2)/(3-1)).%

    mark
This discussion has been closed.