SOLUTION: STATISTIC QUESTION:CONSIDERED A BINOMIAL RANDOM VARIABLE WHERE THENUMBER OF TRIALS IS 12 AND THE PROBABILITY OF SUCCESS ON EACH TRIAL IS 0.25 . FIND THE MEAN AND STANDARD DEVIATION

Hi,

Best to separate what we have to work with: rules, principals,distributions,

definitions, rules governing combinations & permutations etc 

and what decisions need to made to apply what we have to work with. 



First question is handled using the definition of the mean and standard deviation

for a Bionaomial Distribution

STATISTIC QUESTION:CONSIDERED A BINOMIAL RANDOM VARIABLE WHERE THENUMBER OF 

TRIALS IS 12 AND THE PROBABILITY OF SUCCESS ON EACH TRIAL IS 0.25 . 

FIND THE MEAN AND STANDARD DEVIATION OF THE RANDOM VARIABLE.

P = nCx* * where p and q are the probabilities of success and failure 

respectively. In this case both p = .25 or 1/4

nCx = 

Definition of mean = n*p = 12*(1/4) = 3

Definition of standard deviation = 



Second question: How many different combinations

"IF I GO INTO AN ICREAM PARLOR ,AND I HAVE THE CHOICE OF HAVING ONE OF 10 DIFFRENT FLAVORS , WITH ONE OF 5 TOPINGS AND ONE OF 3 DIFFRENT TYPES OF CONES, HOW MANY TIMES CAN I COME BACK TO THIS PLACE AND GET A DIFFRENT ICE CREAM CONE COMBINATION?

Flavors = 10   Toppings = 5   Cone type = 3

different combinations of ice cream cones =10*5*3 = 150



Third question: Probability involving "and"

3THERE ARE 10 COLORED BALLS IN A BOX(5RED,3BLUE,2GREEN). WHAT IS THE PROBABILITY 

OF PICKING OUT THE RED BALL THEN A BLUE BALL (IF I DONOT REPLACE THE RED BALL)?

P(first is a red ball)= 5/10 or 1/2

P(Blue ball with a red one on gone)= 3/9 or 1/3

P(red and then blues)= (1/2)*)1/3) =1/6

Hope this helps.