AP Statistics
posted by Laura .
Of all U.S. fourth graders, 71% are assigned mathematics homework three or more times per week. If 5 fouth graders are randomly selected to be checked for this frequency of homework assignment during a randomly chosen week, find the probability that
A.) exactly one fourth grader was assigned homework three or more times that week
B.) no fourth grader was assigned homework three or more times that week
C.) at least one fourth grader was assigned homework three or more tiems that week

a)
NNNNY
NNNYN
NNYNN
NYNNN
YNNNN
so, there are five ways to sort the fourth graders
Pr(one)=5*.71*.29^4=.0251 check that.
b)Pr(none)=.29^5
c) Pr(at least one)=1Pr(none) 
A. .0251
B. .0020
C. None
Respond to this Question
Similar Questions

statistics
a mathematics professor wishes to analyze the relationship between the number of papers graded by his department's student homework graders an the total amount of money paid to the graders. He collects data for 12 randomly chosen graders … 
math
Ok, the problem says: a Middle school has 125 6th graders, 150 7th graders, and 100 8th graders. Which statement is NOT true? 
statistics
First graders who misbehave in school may be more likely to be regular smokers as young adults according to a new study presented in the July 2004 issue of the American Journal of Epidemiology. After following a group of U.S. first … 
Math
There were 20 more fifth graders then fourth graders. 140 students from both grades. How many fifth graders were there? 
mATH
First graders who misbehave in school may be more likely to be regular smokers as young adults according to a new study presented in the July 2004 issue of the American Journal of Epidemiology. After following a group of U.S. first … 
math
83 3rd graders 115 4th graders 150th graders all the 5th graders will be on one side and all the 4th graders will be on the other side the 3rd graders will be split up so that the two sides will have equal number of student how many … 
Math
The twoway table shows the number of fourth and fifth graders who do or do not have a savings account. What percent of fourth graders have a savings account? 
Math Prob Stat
The amount of time a student spends completing homework per week their senior year is normally distributed with a mean of 5 hours and a standard deviation of 1.4 A. Find the probability a randomly selected student spends less than … 
Statistics
The amount of time the university professors devote to their jobs per week is normally dis tributed with a mean of 52 hours and a standard deviation of 8 hours. (a) What is the probability that a professor works for more than 56 hours … 
statistic
Im confusing the questions with and / or. table: Grade level  Bird  Cat  Dog  Fish 6th graders  9  27  42  3 7th graders  12  36  56  4 1. what is the probability randomly selected student is an 7th grader and prefers a …