Harvest Moon: Friends of Mineral Town

Harvest Goddess Game Guide
Copyright 2010 Brian McCloud
aka MauveCloud (mauvecloud [at] mauvecloud [dot] net)

Version 1.20
Last Update: Monday, July 12, 2010

Purpose:
This attempts to explain the "Harvest Goddess Game", and list all possible
prizes for a given number of wins. Some other guides available through
http://www.gamefaqs.com/ include mention of this mini-game, but those seem
incomplete and/or inaccurate compared with my observations. Also, it seemed
that nobody else had made a guide exclusively for this mini-game.

Sources:
Prices for items were found in the guide by Samurai Goroh & thekingofthisgame,
which is available at
http://db.gamefaqs.com/portable/gbadvance/file/harvest_moon_fomt_d.txt
The items available for each number of wins up to 21 have so far been compiled
by me, using the actual cartridge on a GameCube Game Boy Player setup.
However, I have a few gaps, and I mostly haven't bothered trying for ones
above 14, since most of those can't be sold.

How to play:

The game can be accessed on the left channel of the TV on some days (at least
until the 5th of Spring). Sometimes the game show will appear right away, but
other times I have to press left a few times (I think as many as 9 sometimes)
to get it to appear.

For each round, a digit between 0 and 9 will be chosen (randomly, as far as I
can tell). That digit will be shown 14 times across and 3 times down (for a
total of 42 copies of the digit). You have to predict whether the next digit
chosen will be higher or lower. If you get it right, it will count as a win
and you can continue playing. If the next digit chosen is the same as the
previous digit, it will not be counted as a win, but you can still continue
playing. If you predict incorrectly, the game ends, and the number of wins
will determine your prize (if any).

If the digit is 0-4, the odds are in favor of the next digit being larger. If
the digit is 5-9, the odds are in favor of the next digit being smaller. Once
you have accumulated enough wins for the item you want, you might want to try
to lose, especially if the prizes for more wins can't be sold.

Once you have played 5 times in one day, she says "That's it for today. Bye
now." when you try to access her game show. However, any time you are not
satisfied with the prize you won, you can use the diary's "load" feature to go
back to before you won it and try again (provided you remembered to save
before playing, and after each time you get a satisfactory prize).

Possible Prizes(amount to sell for):
Wins    Prize
0-1     Nothing!
2       Black Grass (10G), Blue Grass (100G), Green Grass (100G),
        Indigo Grass (100G), Orange Grass (100G), Purple Grass (120G),
        Red Grass (110G), White Grass (150G), Yellow Grass (120G)
3-9     Buckwheat Flour (n/a), Rice Cake (n/a)
10-14   Relaxation Tea Leaves (1,000G)
15      Sunblock (n/a)
16      Sunblock (n/a)
17      Sunblock (n/a)
18      Sunblock (n/a)
19      Sunblock (n/a)
20      Skin Lotion (n/a)
21      Skin Lotion (n/a)
22      Skin Lotion (n/a)
23      Skin Lotion (n/a)

I have not yet confirmed the prizes below, but the guide by Samurai Goroh &
thekingofthisgame lists the items with ranges of wins.

25-29   Facial Pack (n/a)
30-39   Perfume (n/a)
40-49   Dress (n/a)
50-59   Golden Lumber (n/a)
60-69   Fossil of Ancient Fish (5,000G)
70-79   Pirate Treasure (10,000G)
80-89   Recipe for Ketchup (n/a)
90-99   Recipe for French Fries (n/a)
100+    Book (n/a)

Note: "n/a" does not mean I don't know the amount it sells for. It means that
the item cannot be dropped into the shipping box and sold, so you can't get
any money for it! You might be able to use the item in other ways, though.

Probabilities for sellable items (if you try to stop after the lowest 
number of wins to get the item):
Colored Grass           47.05% (about a 1 in 2 chance)
Relaxation Tea Leaves    8.10% (about a 1 in 12 chance) 
Fossil of Ancient Fish   2.83e-5% (about a 1 in 3.5 million chance)
Pirate Treasure          2.29e-6% (about a 1 in 43.7 million chance)

The formula I used to determine the above probabilities was:
P[W] = (7/9)^W when W < T
P[W] = (7/9)^T * (2/9)^(W-T) * (7/9) when W >= T
Where P[W] is the probability for a given number of wins, W is the number of
Wins achieved, and T is the target number of wins. 

However, the formula above is assuming a good pseudo-random number generator 
with equal probability of each digit. If someone wants to prove that assumption
wrong and show that knowing enough digits will reveal the rest of the sequence,
my email is near the top of this guide.