In a survey to determine the smoking habits of first–year students, the number of cigarettes?

that they smoked each


day was counted. The back–to–back stem–and–leaf plot below shows the data collected.





http://i55.photobucket.com/albums/g154/A...





8.1 How many students were questioned in this survey?





8.2 How many men smoked less than 20 cigarettes each day?





8.3 How many female students smoked more than 30 cigarettes each day?





Q9





There are 2 blue pens, 3 red pens and 2 green pens in a closed box. Suppose you draw two pens together without


first looking at the pens. Use Bk , Rl and Gm to denote a blue, red or green pen respectively, where k, l or m denotes


a certain blue, red or green pen, i.e. B1 and B2 denote the two blue pens, etc.





9.1 What is the sample space S in this case? (Give it as a set.)





9.2 Write down n (S), the number of outcomes in S.





9.3 Write down as a set the event E "drawing a red and a green pen".





9.4 Write down n (E) , the number of elements in E.





9.5 What is the probability that you will draw a red and a green pen together?

In a survey to determine the smoking habits of first–year students, the number of cigarettes?
Hi,





8.1 How many students were questioned in this survey?





There are 20 men and 20 women for a total of 40 students surveyed.





8.2 How many men smoked less than 20 cigarettes each day?





None of the men smoked less than 20 cigarettes a day. The least for any of the men was 20.





8.3 How many female students smoked more than 30 cigarettes each day?





10 of the women smoked more than 30 cigarettes per day. They smoked from 31 to 51 cigarettes each day.








Q9





There are 2 blue pens, 3 red pens and 2 green pens in a closed box. Suppose you draw two pens together without


first looking at the pens. Use Bk , Rl and Gm to denote a blue, red or green pen respectively, where k, l or m denotes


a certain blue, red or green pen, i.e. B1 and B2 denote the two blue pens, etc.





9.1 What is the sample space S in this case? (Give it as a set.)








S = {B1B2, B1R1, B1R2, B1R3, B1G1, B1G2, B2R1, B2R2, B2R3 , B2G1, B2G2, R1R2, R1R3, R1G1, R1G2, R2R3, R2G1, R2G2, R3G1, R3G2, G1G2}








9.2 Write down n (S), the number of outcomes in S.





n(S) = 21





9.3 Write down as a set the event E "drawing a red and a green pen".





E = {R1G1, R1G2, R2G1, R2G2, R3G1, R3G2}





9.4 Write down n (E) , the number of elements in E.





n(E) = 6





9.5 What is the probability that you will draw a red and a green pen together?





6/21 = 2/7 or 28.57%





I hope that helps!! :-)