Spinning penny page

Spinning penny page (as of October 24, 2004)

Spinning penny*: Proportion of heads p = (??)   Sample data: Students spun pennies 50 times each.
                                                       Fall 1999 pooled   13 students      p-hat = 321/650 = .4938
                                              Spring 2001 pooled 15 students      p-hat = 398/750 = .531
                                                           Fall 2001 Math 251   7 students p-hat = 174/350 = .497
                                                          Fall 2001 Math 151   9 students   p-hat = 229/450 = .509
                                              Pooled all       43 previous      students   p-hat =1122/2150 = .522
Flicked:    Spring 2002 7 students p-hat = 157/350 = .449
                       Without the "10H" outlier: p-hat = 147/300 = .49
                   Fall 2002 6 students p-hat = 151/300 = .503
                   Spring 2003 7 students p-hat = 151/350 = .431
                    Spring 2004 1 student p-hat =24/50 = .48
                    Fall 2004 5 students p-hat =123/250= ..49
                  Pooled 26 students p-hat = 606/1300 = .466
Twirled: Spring 2002 13 students p-hat = 296/650 = .455
                   Fall 2002 8 students p-hat = 183/400 = .458
                  Spring 2003 13 students p-hat = 308/650 = .474
                  Spring 2004 8 students p-hat = 209/400 = 0.523
Fall 2004 3 students p-hat = 66/150 = .44
                  Pooled 45 students p-hat = 996/2250 =.472
Both: Spring 2004 4 students p-hat = 101/200 =.505
           Fall 2004 1 student p-hat = 26/50 = .52
            Pooled 5 students p-hat = 127/250 =.508
Other: 2 did only 30, 1 did a nickel.

Combined flicked & twirled & both last 5 terms 76 students, p-hat = 1795/3800 = .472

Sampling variability: Distribution of all individual students' p-hats, Proportion of heads/50
flicks marked with x, Fall 02+ Spring 03, Spring 04, Fall 04

o-+- .20 -+- .22 -+- .24 -+- .26 x
-+- .28 o
-+- .30 o
o
o
-+- .32
x
-+- .34
o
-+- .36 o
x
o
o
-+- .38 o
e
o
o
-+- .40 e
o
o
o
o
x
o
o
-+- .42 o
o
o
o
o
o
o
o
-+- .44 o
x
o
o
x
o
o
o
o
o
o
o
o
-+- .46 x
o
x
x
x
o
o
o
-+- .48
x
x
o
x
o
o
o
o
o
o
o
o
o
o
o
-+- .50
ex
x
o
o
o
o
o
o
o
o
o
o
o
o
o
o
-+- .52 e
e
o
x
o
x
o
o
o
o
o
o
o
o
o
o
-+- .54 o
o
o
o
o
-+- .56 o
o
o
o
o
-+- .58 o
-+- .60 o
o
-+- .62 o -+- .64 -+- .66 o
.74e -+- .68+

- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
Flicked:
Fall 02, Spring 03, 7 students, Spring 04, 1 student, Fall 04, 5 students

-+- .20 -+- .22 -+- .24 -+- .26 x
-+- .28 -+- .30 -+- .32
x-+- .34
-+- .36 x
x -+- .38 -+- .40 x-+- .42 x-+- .44
x
x-+- .46 x
x
x
x-+- .48 x
x
x-+- .50 x
x-+- .52 x
x-+- .54 -+- .56 -+- .58 -+- .60 -+- .62 -+- .64 -+- .66 -+- .68

- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
Twirled:
Fall 02, Spring 03, 13 students, Spring 04, 8 students, Fall 04, 3 students

-+- .20 -+- .22 -+- .24 -+- .26
-+- .28 o -+- .30 -+- .32
-+- .34
o-+- .36 o
-+- .38 o
o
-+- .40 o
o
o
o
-+- .42 o
o
o
o
o
-+- .44 o
o
o
o
o
o
-+- .46
o-+- .48

o
-+- .50 -+- .52 o
o
o
-+- .54 o
o
o
-+- .56 o
o-+- .58 o
-+- .60 o -+- .62 -+- .64 -+- .66 o -+- .68

Both: Spring 04, 5 students, Fall 04, 1 student

-+- .20

-+- .22

-+- .24

-+- .26

-+- .28

-+- .30

-+- .32

-+- .34

-+- .36

-+- .38

e
-+- .40

e
-+- .42

-+- .44

-+- .46

-+- .48

-+- .50

e -+- .52

ee
-+- .54

-+- .56

-+- .58

-+- .60

-+- .62

-+- .64

-+- .66

.74 -+- .68+

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Spinningpenny04.htm

10/24/04

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*Text answer book says (flicked) spinning pennies often approach 40% heads in the long term. Not here, yet. Are Wells Women different?!