Saturday

January 31, 2015

January 31, 2015

Posted by **Anonymous** on Friday, June 1, 2007 at 1:40pm.

How would I do this question??

I presume you mean that there is a 5% chance that a student, drawn at random, will have lice.

You could solve this exactly as a combinatorial problem. The probability of seeing exactly 6 is:

(.95^114 * .05^6)*Z, where Z is 120!/(6!*114!) (where ! means factorial). Repeat for exactly 7 and exactly 8.

Or you could solve approximately and use the properties of a binominal distribution. Here, the expected mean is .05*120=6, the standard deviation is sqrt(120*.05*95)=2.37 So, 8 is .84 standard deviations away from the mean. Use a cumulative normal distribution table to find your probability. (But, I wouldnt use 8, I would use 8.5)

**Answer this Question**

**Related Questions**

Grammar - Mother wondered from __________ her children had gotten the head lice...

Math - The table shows the number of classrooms needed for different numbers of ...

English - I have to write my cure for an "ill" that plague teenagers. This one ...

childcare - 14. Caregivers shouldn't allow dress-up play with hats when _______ ...

math - (Mad +lice)+(equations + r +p - square)= decimal_______

science - How bad are lice really for your health and can they cause any major ...

math - (Math+lice)+ (equations+R+P- Square)= Decimal_______ I don't have a clue ...

Sexually Transmitted Infections - What are the temporary and longterm effects of...

Ms.Sue - Yesterday I wasn't able to post so I here I am posting it today for you...

unscramble grammar - I need help descrambling 2 sentences: 1 - insects plant eat...