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StatisticsHello :) Can you help me please about the next exercise: For 25 students, math scores and physics scores were recorded, the average of the two exams was identical, which is 75, and the standard deviation of the two exams was identical too, which is 12. What is the value of pearson correlation coefficient? (if it exists). I tried to find it, but I did not succeed. In my opinion - it doesn't exist, because I don't have enough data from the question. I'm not sure, it's just my opinion, maybe I'm missing something. Thanks! |

You aren't told, and there is no way of determining, whether the two scores are independent. If they are independent the correlation coefficient is zero as $E[P M] = E[P]E[M]$ Without having you hands on the joint distribution in some form you can't compute the correlation. |

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I understood the word, but i didn't understand what did you mean. |

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I don't know how this is possible. Revisit your text. Independence of random variables is a fundamental concept. |

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But why the answer is 0? |

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when $E[MP]=E[M]E[P]$ |

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