For five individuals the blood platelet aggregation was measured before (x1) and after (y1) they performed a certain task. these five pairs of values gave the following results: ¯x1 = 30.2, y¯1 = 39.0, cov(x1, y1) = 88.5. for another six individuals the blood platelet aggregation was also measured before (x2) and after (y2) they performed the same task. these six pairs of values gave the following results: ¯x2 = 52.17, y¯2 = 63.67, cov(x2, y2) = 148.67. find the covariance of the combined 11 pairs.

-362

step-by-step explanation:

(12)(4)+2(12)-34(12)+2(12)-3

  \/         \/         \/         \/

  48 +   24 -   408 + 24 - 3

      \   /               \   /

          72     -     432 - 3 = -363

well if he bought them at 5 cedis each sold them at 7 cedis each then he would make a profit of 2 cedis of each book. if in total he made 150 cedis profit that means he sold 75 books. he lost 12 books at the start so that means he originally bought a total of 82 books.

step-by-step explanation: