Math Question (4 Questions)?

1.) A football team has a 60% chance of winning when it doesn't snow but only a 40% chance of winning if it does snow. Suppose there is a 60% chance of snow. WHAT IS THE PROBABILITY THAT THE TEAM WILL WIN?





2.) The senior class is 62% female. 35% of the females play a competitive sport. FIND THE PROBABILITY THAT A STUDENT PLAYS A COMPETITIVE SPORT, GIVEN THE STUDENT IS FEMALE?





3.) The daily power usage for 6 days in June were: 51.8, 53.6, 54.7, 50.9, 55.2, and 51.1. FIND THE STANDARD DEVIATION FOR THESE DATA. WHICH DATA FALL WITHIN STANDARD DEVIATION FROM THE MEAN?





4.) Scores on an exam are normally distributed with a mean of 76 and a standard deviation of 10. In a group of 240 students, HOW MANY STUDENTS SCORE ABOVE 96?

Math Question (4 Questions)?
These are hard... *:-)
Reply:1.) 36%





2.) 21.7%
Reply:1)PROBABILITY THAT THE TEAM WILL WIN WHEN THERE IS SNOW IS





Prob of snow=60%


so the reqd probablity is 60%*40%=24%








2)PROBABILITY THAT A STUDENT PLAYS A COMPETITIVE SPORT, GIVEN THE STUDENT IS FEMALE





62%*35%=21.7%





3)calculate the mean





add 51.8, 53.6, 54.7, 50.9, 55.2, and 51.1. %26amp; divide by 6


=52.88





to calculate the standard deviation from


mean


n n-mean (n-mean)^2


51.8 -1.08 1.1664


53.6 0.72 0.5184


54.7 1.82 3.3124


50.9 -1.98 3.9204


55.2 2.32 5.3824


51.1 -1.78 3.1684


317.3 17.4684





sqrt[(n-mean)^2/N]


sqrt[17.4684/6]=sqrt[2.911]


1.706





standard deviation is 1.706
Reply:ans to ques1:: see the team will can in two cases


a) it rain and team wins


b) it doesn't rain and team wins





so as 'raining' and 'team's winning' are independent events therefore if


p1:probability of snow


p2: probability of the team winning without snow


p3:team winning with snow


p4: probability of no snow


therefore total probability is


p=p4*p2 + p1*p2


p=(1--0.6)*0.6 + 0.6*0.4








ans to ques2::probability =ways of selecting a female playing sport divided by total wayts of selecting a student





suppose there are 100 students in total





now its very easy.......ways of selecting a female strudent playing a sport are=girls playin a sport


=.35*62


and total ways are 100


so you got the answer.....i hope so





and ihv no idea of deviation my statistics is poor........so sorry for that

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