KA P/S Type 1 Error passage question

Can someone walk me through their thinking process of this one?
I understand that a Type 1 error is a "false positive" aka a "false alarm",
that Miller's Law (the null hypothesis) says 7 +/-2 items is what one can remember,
and that the average for the study was merely 4.73 items remembered.

Also, in this study, what could be an example of a Type II error (a false negative)?

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KA P/S Type 1 Error passage question