Test item is acceptable when its facility index/difficulty level ranges from ______?

Test item is acceptable when its facility index/difficulty level ranges from ______?

ٹیسٹ آئٹم قابل قبول ہے جب اس کی سہولت انڈیکس/مشکل کی سطح ______ سے ہوتی ہے؟
Explanation

A test item with difficulty between 30% and 70% is neither too hard nor too easy.

This range ensures the item effectively discriminates between high and low achievers.