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authorLouise Crow <louise.crow@gmail.com>2013-09-24 11:29:31 +0100
committerLouise Crow <louise.crow@gmail.com>2013-09-24 11:29:31 +0100
commitd8deb8418b4cd26c68eb1301959e156c19b111e2 (patch)
tree99c346db95d17be9c5105ce47d5f3ac8e943e952 /spec/lib
parent8459314b691f5b02277035219cd58f510d100a77 (diff)
parent75542416a1cc36b353ade557b1bc4f729b02423a (diff)
Merge branch 'release/0.14'0.14
Conflicts: locale/bg/app.po locale/fr/app.po locale/fr_CA/app.po locale/he_IL/app.po locale/hr/app.po locale/it/app.po locale/nb_NO/app.po locale/pl/app.po locale/sv/app.po locale/vi/app.po
Diffstat (limited to 'spec/lib')
-rw-r--r--spec/lib/confidence_intervals.rb30
1 files changed, 30 insertions, 0 deletions
diff --git a/spec/lib/confidence_intervals.rb b/spec/lib/confidence_intervals.rb
new file mode 100644
index 000000000..cb8717f3d
--- /dev/null
+++ b/spec/lib/confidence_intervals.rb
@@ -0,0 +1,30 @@
+require 'confidence_intervals'
+
+describe "ci_bounds" do
+
+ describe "when passed all successes" do
+ it "should never return a high CI above 1" do
+ ci = ci_bounds 16, 16, 0.01
+ ci[1].should be <= 1
+ end
+ end
+
+ describe "when passed all failures" do
+ it "should never return a low CI below 0" do
+ ci = ci_bounds 0, 10, 0.05
+ ci[0].should be >= 0
+ end
+ end
+
+ describe "when passed 4 out of 10 successes (with 0.05 power)" do
+ it "should return the correct Wilson's interval" do
+ # The expected results here were taken from an online
+ # calculator:
+ # http://www.vassarstats.net/prop1.html
+ ci = ci_bounds 7, 10, 0.05
+ ci[0].should be_within(0.001).of(0.3968)
+ ci[1].should be_within(0.001).of(0.8922)
+ end
+ end
+
+end