Statistics::Basicの使い方

解説そのままだけど，毎回英語読むのはしんどいので書いておく。

NAME

とっても基本的な統計関数だよ！！

SYNOPSYS

こんな関数があるよ！！

# ひとつのベクトルに対するメソッド
  Statistics::Basic::Mean;      # 平均
  Statistics::Basic::Median;    # 中央値
  Statistics::Basic::Mode;      # 最頻値
  Statistics::Basic::Variance;  # 分散
  Statistics::Basic::StdDev;    # 標準偏差

# ふたつのベクトルに対するメソッド
  Statistics::Basic::CoVariance;   # 共分散
  Statistics::Basic::Correlation;  # 相関

EXAMPLE

例はもうそのままだ！手抜きです

my $mean = Statistics::Basic::Mean->new($array_ref)->query;

print "$mean\n";  # hooray

# That works, but I needed to calculate a LOT of means for a lot of
# arrays of the same size.  Furthermore, I needed them to operate FIFO
# style.  So, they do:

my $mo = new Statistics::Basic::Mean([1..3]);

print $mo->query, "\n"; # the avearge of 1, 2, 3 is 2
  $mo->insert(4);   # Keeps the vector the same size automatically
print $mo->query, "\n"; # so, the average of 2, 3, 4 is 3

# You might need to keep a running average, so I included a growing
# insert

  $mo->ginsert(5);  # Expands the vector size by one and appends a 5
print $mo->query, "\n"; # so, the average is of 2, 3, 4, 5 is 7/2

# And last, you might need the mean of [3, 7] after all the above

  $mo->set_vector([2,3]);  # *poof*, the vector is 2, 3!
print $mo->query, "\n"; # and the average is now 5/2!  Tadda!

# These functions all work pretty much the same for ::StdDev and
# ::Variance but they work slightly differently for CoVariance and
# Correlation.

# Not suprisingly, the correlation of [1..3] and [1..3] is 1.0

my $co = new Statistics::Basic::Correlation( [1..3], [1..3] );

print $co->query, "\n";

# Cut the correlation of [1..3, 7] and [1..3, 5] is less than 1

  $co->ginsert( 7, 5 );
print $co->query, "\n";