Question

445 college students were classified according to both frequency of marijuana use and parental use of alcohol and psychoactive drugs (from the article \marijuana use in college\, youth and society, 1979: 323 - 334). the data are represented in the contingency table shown below.

parental usage	count	never	occasional	regular	total
neither		141	54	40	235
one		68	44	51	163
total		226	109	110	445

which of the following is the conditional distribution of student usage level when parental usage = one?

○ never = 68/445; occasional = 44/445; regular = 51/445
○ never = 144/235; occasional = 54/235; regular = 40/235
○ never = 141/226; occasional = 54/109; regular = 40/110
○ never = 68/163; occasional = 44/163; regular = 51/163

Explanation:

Step1: Recall conditional - distribution formula

For a conditional distribution of student usage level given parental usage = One, we divide the number in each student - usage category (Never, Occasional, Regular) by the total number of students with parental usage = One.

Step2: Identify relevant numbers

The total number of students with parental usage = One is 163. The number of 'Never' users is 68, 'Occasional' users is 44, and 'Regular' users is 51.

Answer:

Never = 68/163; Occasional = 44/163; Regular = 51/163