Statistics Practice: Discrete Expected Values

Statistics Practice: Discrete Expected Values

Choose one exact numerical answer in the unit requested. Fractions such as 3/2 mean an exact value; no rounding unless requested. All 20 questions appear in random order. Practice target: 16/20. These are focused mathematics exercises, not a complete examination.
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A random score is 5 with probability 1/4 and 13 with probability 3/4. What is its expected value?