Sa'id bin al-Musayyib (may Allah have mercy on him) said: A Bedouin came to the Messenger of Allah (peace and blessings be upon him), and he mentioned (the story of) the one who had gone to his wife in the month of Ramadan. Ata (may Allah have mercy on him) said: I asked Sa'id (may Allah have mercy on him): How much was in the basket? He said: Between fifteen and twenty sa'.
The hadith of Ibn al-Musayyib is munqati' (its chain is broken), and others are more reliable than Ata al-Khurasani.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الأيمان / 19969