group members

In a group of 20 members, 12 are boys and 8 are girls. Find the number of ways of forming a 15 member committee which should include 9 boys. => 1 2 C 1 5 or 2 0 C 1 5 or ( 1 2 P 8 )( 9 P 2 ) or ( 1 2 C 9 )( 8 C 6 )..

What sampling method was used by a researcher who divided subjects into two groups according to gender and then selected members from each group for her sample? => cluster or stratified or random or systematic..

A group of 440 members registered for the Conference on "Global Warming". 70% of the members attended the inaugural lecture. Estimate the number of persons who attended the lecture. => 308 or 358 or 320 or None of the above..

Lithium is the hardest of all the alkali metals. The melting and boiling points of lithium are much higher than those of other elements of Group 1. Lithium is less reactive as compared to other metals and it does not get tarnished readily in air. It forms only monoxide, Li 2 O ..

The members of a certain group possess similar properties but the reactivity may differ, e.g., in case of group I A the reactivity increases as we move down the group from lithium to cesium but in case of VII A it decreases from fluorine to iodin..

1. Valence shell electrons On moving down the group the valence shell electrons remain the same. 2. Valency The valency of all the members of a particular group is same. 3. Properties of elements The members of a certain group possess similar proper..

1. Oxygen is the first member of the group VIA and sulphur is the second member of the group VIA. 2. Other member of this group are selenium, tellurium and poloniu..

Unlike boron, the other members of the group are metallic and the electropositive character increases as we go down the group. All these elements in their compounds exhibit the oxidation state of + 3 and +1. The important chemical properties of the boron family are dis..