When ESP does not exist then the population mean would be 20

When ESP does not exist, then the population mean would be 20. This is the expected value for the number of cards (out of 100) correctly identified by chance or guessing. What are the null and alternative hypotheses to test the hypothesis that ESP exists (use a two-tailed alternative)?

Solution

20.
with ESP, you can guess more cards, so Ha must have >:

A: Ho: u = 20 vs Ha: u > 20. [ANSWER]