Tutors Answer Your Questions about Probabilityandstatistics (FREE)
Question 440446: If I have a 5 yr. old boy who has a BMI of 18 and the BMI is considered a normally distributed variable, whose mean for this age boy is 15.41914 and whose standard deviation is 0.075992. How can I calculate the PERCENTILE ranking for this boy. Please show me HOW you achieve the numbersI need to see HOW to calculate the resultPLEASE DO NOT USE A TABLE. I want to write an excel program for our school nurse and I need the EQUATION to plug in and test for in excel. Thank you.
Click here to see answer by stanbon(69061) 
Question 440489: The theoretical probability of undesirable side effects resulting from taking Grebex is 1 in 20. If 100 people take Grebex to lower their blood pressure, how many will encounter undesirable side effects?
Click here to see answer by edjones(8007) 
Question 440511: a bag contains 10 marbles (4 red, 2 white and 4 blue). if you select 3 marbles at random from the bag without replacement, what is the probability ( as a common fraction) that exactly two of the marbles selected will be red?
Plz help me fast this problem is killing me!
Click here to see answer by edjones(8007) 
Question 440592: Consider the experiment of drawing two cards without replacement from an ordinary deck of 52 playing cards....what are the ODDS in favor of drawing a spade and a heart?
This is what I have: P(Spade)=13/52, P(heart without replacement)=13/51 so then I multiply and get 169/2652 reduced to 13/204. Now that is the probability of getting a heart and a spade, how to I find the odds? The formula for finding odds in favor is P(A)/1P(A), so would my problem be set up as
(13/204) / 1(13/204)? If thats how it is set up, how do I carry out the math? I am very confused, please help! The answer in the book is 13:91 but I can not figure out how they got there.
Click here to see answer by richard1234(6688) 
Question 440784: problem 1) Ninety students will graduate from Lima Shawnee High School this spring. Of the 90 students, 50 are planning to ttend college. Two students are to be picked at random to carry flags at graduation.
A) What is the probability both of the selected students plan to attend college?
B) What is the probability one of the two selected students plans to attend college?
I know that these are counting problems that involve the basic counting rule, permutations and combinations. I need the formulas and answers. I am extremly lost.
problem 2) a survey of undergraduate students in the Shool of Business at Northern University revealed the following regarding the gender and majors of the students.
Gender Accounting Management Finance total
Male 100 150 50 300
Female 100 50 50 200
total 200 200 100 500
A) What is the probibility of selecting a female student?
B) What is the probability of selecting a finance or accounting major?
C) What is the probability of selecting a female or an accounting major? Which rule of addition did you apply?
D) Are gender and major independent? Why?
E) What is the probability of selecting an account major, given that the person selected is a male?
F) Suppose two students are selected randomly to attend a lunch with the president of the university. What is the probability that both of those selected are accounting majors?
Problem 3) Reynolds Construction Company has agreed not to erect all "lookalike" homes in a new subdivision. Five exterior designs are offered to potential home buyers. The bulider has standardized three interior plans that can be incorporated in any of the five exteriors. How many different ways can the exterior and interior plans be offered to potewntial home buyers?
Problem 4) A puzzle in the newspaper presents a matching problem. The names of 10 in one U.S. presdents are listed in column, and their vice presidents are listed in random order in the second column. The puzzle asks the reader to match each president with his vice president. If you make the matches randomly, how many matches are possible? What is the probability all 10 of your matches are correct?
Thank you in advance for this much needed help.
Click here to see answer by stanbon(69061) 
Question 440809: I need someone to show me how to do these homework questions please.
5. Suppose an A is worth 4 points, a B 3 points, a C 2 points, a D 1 point, and an F 0 points. If I earned A’s in 60%, B’s in 25%, C’s in 10%, and D’s in 5% of the college credits I have completed, what’s my GPA (one digit after decimal point)?
Suppose the life of a certain brand of vacuum cleaner is normally distributed with a mean life of 12 years and a standard deviation of 4 years. A vacuum cleaner is randomly chosen.
7. Find the probability that it will last less than 10 years (4 digits after decimal point).
8. Find the probability that it will last more than 16 years (4 digits after decimal point).
Click here to see answer by edjones(8007) 
Question 440866: The time spent waiting in the line is approximately normally distributed. The mean waiting time is 7 minutes and the standard deviation of the waiting time is 2 minutes. Find the probability that a person will wait for less than 11 minutes. (Round your answer to 4 decimal places)
Click here to see answer by stanbon(69061) 
Question 440625: suppose you are dealt a hand of three cards at random from a deck of 32 cards consisting of 4 aces, 4 2s, 4 3s and so on up to 4 8s. what is the probability that your hand will have atleast 2 4s? what is the probability that none of your cards will have the same numeric value?
i tried (4/32)(3/31) for the first one and it was wrong
i tried (1/32)(1/31)(1/30) for the second but that didn't work either
Click here to see answer by scott8148(6628) 
Question 5081: Helphow do i figure this one out? Driving me crazy !!!
Twenty bearded men gather. Ten have eightinch beards, six have teninch beards, and four have twelveinch beards. What is the expected length of a randomly selected man from this group?
Tried 10/20 x 6/20 x 4/20 =12inches, that doesn't seem right. Please help!
Click here to see answer by JWG(21) 
Question 441203: 3.18 Suppose A and B are events with 0 < P(A) < 1 and 0 < P(B) < 1.
a. If A and B are disjoint, can they be independent?
b. If A and B are independent, can they be disjoint?
c. If A ⊂ B, can A and B be independent?
d. If A and B are independent, can A and A ∪ B be independent
Click here to see answer by robertb(4061) 
Question 441206: kamal and monica appeared for an interview for two vacancies. the probability of kamal's selevtion is 1/3 and that of monica's selection is 1/5. find the probability that only one of them will bw selected.
Click here to see answer by Euler(11) 
Question 441142: The standard deviation of test scores on a certain achievement test is 11.4. A random sample of 80 scores on this test had a mean of 73.6 . Based on this sample, find a 90% confidence interval for the true mean of all scores. Then complete the table below.
Carry your intermediate computations to at least three decimal places. Round your answers to one decimal place.
What is the lower limit of the 90% confidence interval
What is the upper limit of the 90% confidence interval
Click here to see answer by stanbon(69061) 
Question 441217: three card are drawn is succession without replacement from an ordinary deck of playing cards.find the probability that the first card is red ace,the second card is ten or jack,and the third card is greater than 3 but less than 7.
Click here to see answer by stanbon(69061) 
Question 441166: to test the hypothesis that students who finish an exam first get better grades, professor hardtrach kept tract of the order inwhich papers were handed in, the first 25 papers showed a means of 77.5 with a standard deviation of 19.6, while the last 24 papers handed in showed a mean score of 69.3 with a standard deviation of 24.9 is this significant defference at a=.0? perform a onetail test
Click here to see answer by stanbon(69061) 
Question 441087: The question reads: A university has 10,000 students of which 4,000 are male and 6,000 are female. If a class of 30 students is chosen at random from the university population, find the mean and standard deviation of the number of male students.
After using the formula for binomial distribution mean (np) and standard deviation (square root of np(1p), I came up with the answer...
mean= 12
standard deviation = 2.68
I am confused when to use which equation so I was hoping you could verify my answer. Thank you!
Click here to see answer by stanbon(69061) 
Question 441029: a cooler at a picnic contains 100 cans of soda covered by ice. There are 30 cans of cola, 40 cans of orange soda, 10 cans of ginger ale, and 20 cans of root beer. The cans are all the same size and shape. If one can is selected at random from the cooler, determine the probability that the soda selected is ginger ale.
Click here to see answer by stanbon(69061) 
Question 440997: Country "Text Messages" Population
A "66 billion", "1320 million"
B, "28 billion", "88 million"
C, "14 billion", "292 million"
D, "9 billion", "68 million"
Suppose messages are sent randomly to the people in each country. That is, suppose that the 66 billion messages sent in country A had been randomly delivered to the 1.3 billion people in country A. What's the pobability that a person does not get a tsxt message?
Click here to see answer by stanbon(69061) 
Question 440969: In a poll of 278 registered voters in a certain city, 67% said that they were in favor of a bill which would limit growth and development in their city. Construct a 95% confidence interval for the proportion of voters who are in favor of the bill.
Click here to see answer by stanbon(69061) 

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