OCR MEI S1 — Question 1

Exam BoardOCR MEI
ModuleS1 (Statistics 1)
TopicConditional Probability
TypeBasic two-way table probability

1 An amateur weather forecaster describes each day as either sunny, cloudy or wet. He keeps a record each day of his forecast and of the actual weather. His results for one particular year are given in the table,
\multirow{2}{*}{}Weather Forecast\multirow{2}{*}{Total}
SunnyCloudyWet
\multirow{3}{*}{Actual Weather}Sunny5512774
Cloudy1712829174
Wet33381117
Total75173117365
A day is selected at random from that year.
  1. Show that the probability that the forecast is correct is \(\frac { 264 } { 365 }\). Find the probability that
  2. the forecast is correct, given that the forecast is sunny,
  3. the forecast is correct, given that the weather is wet,
  4. the weather is cloudy, given that the forecast is correct.
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