In Joshua 2:12-13(Mechon Mamre translation) the Torah reads:
12 Now therefore, I pray you, swear unto me by the LORD, since I have dealt kindly with you, that ye also will deal kindly with my father's house (Beit Av)--and give me a true token-- 13 and save alive my father, and my mother, and my brethren, and my sisters, and all that they have, and deliver our lives from death.'
And verse 18 reads:
Behold, when we come into the land, thou shalt bind this line of scarlet thread in the window which thou didst let us down by; and thou shalt gather unto thee into the house thy father, and thy mother, and thy brethren, and all thy father's household (Beit Av).
23 And the young men the spies went in, and brought out Rahab, and her father, and her mother, and her brethren, and all that she had, all her kindred (Mishpachah) also they brought out; and they set them without the camp of Israel. 25 But Rahab the harlot, and her father's household, and all that she had, did Joshua save alive.
From these verses it seems that Mishpachah is part of Beit Av, while from Joshua 7:14-18 it seems that Mishpachah is part of a Shevet and a Beit Av is part of a Mishpachah:
14 In the morning therefore ye shall draw near by your tribes; and it shall be, that the tribe which the LORD taketh shall come near by families; and the family which the LORD shall take shall come near by households; and the household which the LORD shall take shall come near man by man. 15 And it shall be that he that is taken with the devoted thing shall be burnt with fire, he and all that he hath; because he hath transgressed the covenant of the LORD, and because he hath wrought a wanton deed in Israel.' 16 So Joshua rose up early in the morning, and brought Israel near by their tribes; and the tribe of Judah was taken. 17 And he brought near the family of Judah; and he took the family of the Zerahites. And he brought near the family of the Zerahites man by man; and Zabdi was taken. 18 And he brought near his household man by man; and Achan, the son of Carmi, the son of Zabdi, the son of Zerah, of the tribe of Judah, was taken.
Can anyone explain me which makes part of what?