lib/jldrill/model/Quiz/Statistics.rb

Name	Total Lines	Lines of Code	Total Coverage	Code Coverage
lib/jldrill/model/Quiz/Statistics.rb	`316`	`225`	`93.04%`	`90.22%`

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Code reported as executed by Ruby looks like this...and this: this line is also marked as covered.Lines considered as run by rcov, but not reported by Ruby, look like this,and this: these lines were inferred by rcov (using simple heuristics).Finally, here's a line marked as not executed.

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1 require 'jldrill/model/Item'

2 require 'jldrill/model/ItemStatus'

3 require 'jldrill/model/Quiz/Timer'

4 require 'jldrill/model/Quiz/LevelStats'

5 require 'jldrill/model/Quiz/Counter'

7 module JLDrill

9     # Statistics for a quiz session

10     class Statistics

12         attr_reader :estimate, :lastTen, :confidence, :levels,

13                         :timesInTargetZone, :learned, :reviewed

15         attr_writer :learned, :reviewed

17         MINIMUM_CONFIDENCE = 0.009

18         SECONDS_PER_DAY = 60 * 60 * 24

20         def initialize(quiz)

21             @quiz = quiz

22             @estimate = 0

23             @correct = 0

24             @incorrect = 0

25             @lastTen = []

26             @inTargetZone = false

27             @timesInTargetZone = 0

28             @levels = []

29             1.upto(8) do

30                 @levels.push(LevelStats.new)

31             end

32             @learned = 0

33             @reviewed = 0

34             @reviewRateSum = 0

35             @reviewTimer = Timer.new

36             @learnTimer = Timer.new

37             @currentTimer = nil

38             resetConfidence

39         end

41         def record(bool)

42             @lastTen.push(bool)

43             while @lastTen.size > 10

44                 @lastTen.delete_at(0)

45             end

46             if inTargetZone?

47                 @timesInTargetZone += 1

48             else

49                 @timesInTargetZone = 0

50             end

51         end

53         def recentAccuracy

54             retVal = 0

55             if @lastTen.size > 0

56                 0.upto(@lastTen.size) do |i|

57                     if @lastTen[i]

58                         retVal += 1

59                     end

60                 end

61                 retVal = (retVal * 100 / @lastTen.size).to_i

62             end

63             retVal

64         end

66         def inTargetZone?

67             # Don't start the countdown until we have reviewed

68             # at least 10 item.

69             if @reviewed <= 10

70                 return false

71             end

72             if !@inTargetZone

73                 if recentAccuracy >= 90

74                     @inTargetZone = true

75                 end

76             else

77                 if (recentAccuracy < 90) && (@confidence < 90)

78                     @inTargetZone = false

79                 end

80             end

81             return @inTargetZone

82         end

84         # Get the appropriate LevelStat object for this item

85         def getLevel(item)

86             return @levels[Counter.getLevel(item)]

87         end

89         def recordReviewRate(item)

90             @reviewRateSum += item.schedule.reviewRate

91         end

93         def reviewBin

94             return @quiz.contents.bins[4]

95         end

97         def size

98             return reviewBin.length

99         end

101         def averageReviewRate

102             retVal = 1.0

103             if @reviewed != 0

104                 retVal = ((@reviewRateSum * 10).round / @reviewed).to_f / 10

105             end

106             return retVal

107         end

109         def currentReviewRate

110             retVal = 1.0

111             if size > 0

112                 rate = reviewBin[0].schedule.reviewRate

113                retVal = ((rate * 100).round).to_f / 100

114             end

115             retVal

116         end

118         def statsTable

119             dCounter = DurationCounter.new

121             reviewBin.each do |item|

122                 dCounter.count(item)

123             end

124             return dCounter

125         end

127         def correct(item)

128             # currently only level 4 items are reviewed

129             if item.bin != 4

130                 return

131             end

132             @correct += 1

133             @reviewed += 1

134             recordReviewRate(item)

135             level = getLevel(item)

136             if !level.nil?

137                 level.correct

138             end

139             record(true)

140             reEstimate

141             calculateConfidence(true)

142         end

144         def incorrect(item)

145             # currently only level 4 items are reviewed

146             if item.bin != 4

147                 return

148             end

149             @incorrect += 1

150             @reviewed += 1

151             recordReviewRate(item)

152             level = getLevel(item)

153             if !level.nil?

154                 level.incorrect

155             end

156             record(false)

157             reEstimate

158             calculateConfidence(false)

159         end

161         def correct=(value)

162             @correct = value

163             reEstimate

164         end

166         def incorrect=(value)

167             @incorrect = value

168             reEstimate

169         end

171         # Returns the actual % accuracy of the quiz in an integer

172         def accuracy

173             retVal = 0

174             if @incorrect == 0

175                 if @correct != 0

176                     retVal = 100

177                 end

178             else

179                 retVal = ((@correct * 100) / total).to_i

180             end

181             retVal

182         end

184         def total

185             @correct + @incorrect

186         end

188         # Generates an estimate of the % accuracy in an integer

189         def reEstimate

190             hop = ((recentAccuracy - @estimate) * 0.3).to_i

191             retVal = @estimate + hop

192             if (retVal > 100) then retVal = 100 end

193             if (retVal < 0) then retVal = 0 end

194             @estimate = retVal

195         end

197         # Calculates a Bayesian estimate (I think!) of the confidence that

198         # the items seen to this point were known to an accuracy of at

199         # least 90%.

200         #

201         # How this is calculated:

202         #    According to Bayes law, P(H|E) = P(E|H) * P(H) / P(E)

203         #    Where:

204         #       P(H|E) is the probability that the hypothesis is correct

205         #              given the evidence.

206         #       P(E|H) is the probability that the evididence would be

207         #              shown if the hypothesis were correct.

208         #       P(H)   is the probability that the hypothesis is correct

209         #              given any evidence.

210         #       P(E)   is the probability that the evidence would be seen

211         #              in all cases.

212         #

213         #   This value is calculated incrementally in the following fashion:

214         #       P[n] = P(E|H) * P[n-1] / P(E)

215         #   i.e., the nth value of P is dependent on the n-1th value of P

216         #

217         #   In our case, I will assume that the distribution of the

218         #   probabilities is uniform (probably wrong!) and say that

219         #   if we got the question right

220         #        P(E|H) = 0.95

221         #             that is, our probability of getting it right is

222         #             somewhere between 90 and 100%.  I assume uniform

223         #             distribution, therefore the average is in the middle.

224         #   or if we got the question wrong

225         #        P(E|H) = 0.05

226         #             obviously, the probability of getting it wrong given

227         #             the hypothesis is 1 minus the probability of getting

228         #             it right.

229         #        P(E) = sum(probabilities for all the hypotheses)

230         #             = P(chance < 90) + P(chance is 90+%)

231         #        P(chance < 90) = 0.45(1 - P[n-1])

232         #             that is, it's equal to 1/2 the range between 0 and 90

233         #             times the probability that hypothesis is wrong.

234         #        P(chance > 90) = 0.95P[n-1]

235         #             that is, it's equal to 1/2 the range between 90 and 100

236         #             times the probability that the hypothesis is right.

237         #             So...

238         #        P(E) = 0.45(1 - P[n-1]) + 0.95P[n-1]

239         #

240         #    Giving a final answer of

241         #        P[n] = P(E|H) * P[n-1] / (0.45(1 - P[n-1]) + 0.95P[n-1])

242         #

243         #    I fully expect this is completely wrong due to my lack of

244         #    ability in math and statistics.  But on the other hand, I won't

245         #    care much as long as appears from the user's point of view to

246         #    be working.

247         def calculateConfidence(wasCorrect)

248             if wasCorrect

249                 pEH = 0.95

250             else

251                 pEH = 0.05

252             end

253             pE = (0.45 * (1.0 - @confidence)) + (0.95 * @confidence)

254             @confidence = (pEH * @confidence) / pE

255             if @confidence < MINIMUM_CONFIDENCE

256                 @confidence = MINIMUM_CONFIDENCE

257             end

258         end

260         def resetConfidence

261             @confidence = MINIMUM_CONFIDENCE

262         end

264         def startTimer(isReview)

265             if !@currentTimer.nil?

266                 @currentTimer.stop

267             end

268             if isReview

269                 @currentTimer = @reviewTimer

270             else

271                 @currentTimer = @learnTimer

272             end

273             @currentTimer.start

274         end

276         def learnTime

277             @learnTimer.total

278         end

280         def reviewTime

281             @reviewTimer.total

282         end

284         def roundToOneDecimal(value)

285             value = value * 10.0

286             value = value.round

287             value = value.to_f / 10.0

288             value

289         end

291         def learnPace

292             if @learned > 0

293                 roundToOneDecimal(learnTime / @learned)

294             else

295                 0.0

296             end

297         end

299         def reviewPace

300             if @reviewed > 0

301                 roundToOneDecimal(reviewTime / @reviewed)

302             else

303                 0.0

304             end

305         end

307         def learnTimePercent

308             total = learnPace + reviewPace

309             if total > 0

310                 ((learnPace * 100) / total).to_i

311             else

312                 0

313             end

314         end

315     end

316 end

Generated on Mon May 23 16:17:46 +0900 2011 with rcov 0.9.8

Jldrill Git C0 Coverage Information - RCov

lib/jldrill/model/Quiz/Statistics.rb

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