Q140 · Practice questionTechnology-activeComplex unfamiliar5 marks
QUESTION 140 (5 marks)
Let and . Determine the value for which . Hence determine this common probability.
WORKED SOLUTION
5 marksPractice marking scheme
ANSWER
and the common probability is approximately .
Worked solution
Equal opposite-tail probabilities occur when the standardised values are negatives: . Solving gives . Then for , , so the common probability is .
Correctly relates the two standardised values.
Solves for .
Standardises using either distribution.
Finds the common probability.
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