Tutors Answer Your Questions about Probability-and-statistics (FREE)
Question 403485: Suppose that 30 randomly selected subjects are randomly assigned to three different treatment groups, 10 subjects in each. Each group is given one of three different drugs (A, B, or C) and the subjects’ responses are measured on a ratio scale.
We want to know test the hypothesis that the mean group responses are not all equal with a 5% significance level:
Sum ofSquares df MeanSquare F Sig.(p-value)
Between Groups 3.998 2 1.999 5.312 0.011
Within Groups 10.160 27 0.376
Total 14.158 29
F is 5.312 and p value is 0.011
With that result for the F-test, should we reject the null hypothesis given above?
Click here to see answer by stanbon(57967) |
Question 403670: The theoretical probability of undesirable side effects resulting from taking Grebex is 3 in 11. If 110 people take Grebex to lower their blood pressure how many will encounter undesirable side effects?
Click here to see answer by robertb(4012)  |
Question 403729: I am having a problem figuring this out:
How many 11-letter words can you make firm MATHEMATICS?
I have it this far:
11!/2!*2!*2!
Now I know I'm supposed to do this:
11*10*9*8*7*6*5*4*3 (do I stop here or *2 also) since there is a 2 in the denominator
And then cancel out one of the 2 and divide by 4?
Or do I continue with 11*9*8...*2 and divide by 8? If the later why don't I cancel out one of the 2s on the bottom and the one on top? Thanks for all your help.
Kim
Click here to see answer by sofiyac(695) |
Question 403748: Alice and Bob work on a math problem independently. The probability that Alice solves the
problem is 0.8 and the probability that Bob solves it is 0.6.
(a) What is the probability that both solve the problem?
(b) What is the probability that neither solves it?
(c) What is the probability that exactly one of them solves it?
(d) Given that exactly one of them solves the problem, what is the probability that it is
Bob?
A string of Christmas lights has 20 bulbs and if any bulb fails then the whole string goes out.
Suppose that each bulb has a 5% chance of failure during the Christmas holidays and that
the 20 bulbs are independent of each other.
What is the probability that the string of lights will go out during the holidays?
Click here to see answer by stanbon(57967) |
Question 403928: I need some help with these questions.
Mary and jim are taking the same math class and have a quiz coming up next tuesday. The probability that mary studies is 0.8 and the probability that jim studies is 0.7.
1. If Mary and Jim studying are independent events then waht is the probability that mary and jim both study?
2. What is the probability that mary studies if we know that jim studies?
3. What is the probability that mary studies OR jim does not?
Thanks for your help.
Click here to see answer by stanbon(57967) |
Question 403998: If two ratios are formed at random from the four numbers 1,2,4, & 8, what is the probability that the ratios are equal?
(I have already made all of them into fractions... but some are the same! What is an easy way to do this?)
Click here to see answer by stanbon(57967) |
Question 404133: In a multiple choice test, each question has four options, students get 10 points for each correct answer,lose four points for each incorrect answer, and receive no points for unanswered question. the student does not know the answer for one question, is it to her advantage or disadvantage to guess an answer. please show calculation for me
Click here to see answer by stanbon(57967) |
Question 404147: An instructor has graded 23 exam papers submitted by students in a class of 24 students, and the average so far is 72. (The maximum possible score is 100.) How high would the score on the last paper have to be to raise the class average by 1 point?
Click here to see answer by stanbon(57967) |
Question 404165: Justin and Mark share a bedroom. It takes Justin 4 hours to clean the room alone. It takes Mark 3 hours to clean the room alone. When Justin and Mark worked together on the room, they both worked for 45 minutes and then Justin fell asleep. Mark (fearing the wrath of his mother) finished the rest of the job while Justin slept. How long did it take them to finish cleaning the room?
Click here to see answer by josmiceli(9817)  |
Question 404208: You have torn a tendon and are facing surgery to repair it. The surgeon explains the risks to you: infection occurs in 3% of such operations, the repair fails in 14% and both infection and failure occur together in 1%. What percent of these operations succeed and are free from infection?
Click here to see answer by robertb(4012)  |
Question 404205: A driver’s license examiner knows that 75% of all applicants have attended a driving school. If an applicant has attended a driving school, the probability is 0.85 that he or she will pass the license examination, and if an applicant has not attended a driving school, the probability is 0.60 that he or she will pass the examination. What is the probability that an applicant passes the license examination?
Click here to see answer by robertb(4012)  |
Question 404204: Twenty percent of trees in a particular forest have a disease, 30% of the trees are too small to be used for lumber, and 40% are too small to be used for lumber or have a disease. What percent of the trees are too small to be used for lumber, given that they have a disease?
Click here to see answer by robertb(4012)  |
Question 404206: The probability that A occurs is 0.3, the probability that B does not occur is 0.6, and the probability that either A or B occurs is 0.5. Find:
a) The probability that A does not occur.
b) The probability that both A and B occur.
c) The probability that A occurs and B does not occur.
Click here to see answer by robertb(4012)  |
Question 404254: P=12+20In x represents the %of inbound email in the US that is considered spam, where x is the number of years after 2000. Use the model to determine in how many yrs (to 2 decimals places) it will take the % of spam to reach 90%. Use the model to determine the % of spam in the year 2005. Round to 2 decimal places. Please help these are killing me.
Click here to see answer by josmiceli(9817)  |
Question 404289: I have been studying z-scores but this question has me stumped. I have no idea how to find the z-score a a vertical line. This is the question.
Find the z-score location of a vertical line that separates
a normal distribution as described in each of the
following.
a. 20% in the tail on the left
b. 40% in the tail on the right
c. 75% in the body on the left
d. 99% in the body on the right
Click here to see answer by stanbon(57967) |
Question 404580: Essay; show all work. Last fall, a gardener planted 87 iris bulbs. She found that only 72 of the bulbs bloomed in the spring.
Find the empirical probability that an iris bulb of this type will bloom. Give answer as a fraction in lowest terms.
How many of the bulbs should she plant next fall if she would like at least 88 to bloom?
I found the empirical probability, but lost on the second part.
Click here to see answer by stanbon(57967) |
Question 404537: Can someone check my work and let me know if I did it correctly?
Consider the Venn diagram below. The numbers in the regions of the circle indicate the number of items that belong to that region. Since the diagram wont copy, the left circle "A" contains a "70", the right circle "B" contains a "40" and the center, shared space contains a "10".
Determine
• n(A) 70 + 10 = 80
• n(B) 10 + 40 = 50
• P(A) 40 / 120 = 1/3
• P(B) 50 / 120 = 5/12
• P(A|B) 10 / 50 = 1/5
• P(B|A) 10 / 70 = 1/7
Click here to see answer by sudhanshu_kmr(1152)  |
Question 404732: A sample survey of 54 discount brokers showed that the mean price charged for a trade of 100 shares at $50 per share was $33.77. The survey is conducted annually. WIth the histiorical data available, assume a known population standard deviation of $15.
a. Using the sample datta, what is the margin of error associated with a 95% confidence interval?
b. Develop 95% confidence interval for the mean price charged by discount brokers for a trade of 100 shares at $50 per share.
Click here to see answer by stanbon(57967) |
Question 404736: The college board reported the following mean scores for teh three parts of the SAT.
Critical Reading 502
Mathematics 515
Writing 494
Assume that the population standard deviation on each part of the test is o=100
What is the probability a random sample test of 90 test takers will provide a sample mean test score within 10 points of the population mean of 502 on the critical reading part of the test?
I have gotten [502-10, 502=10]= [492,512]
P(492
Click here to see answer by stanbon(57967) |
|
Older solutions: 1..45, 46..90, 91..135, 136..180, 181..225, 226..270, 271..315, 316..360, 361..405, 406..450, 451..495, 496..540, 541..585, 586..630, 631..675, 676..720, 721..765, 766..810, 811..855, 856..900, 901..945, 946..990, 991..1035, 1036..1080, 1081..1125, 1126..1170, 1171..1215, 1216..1260, 1261..1305, 1306..1350, 1351..1395, 1396..1440, 1441..1485, 1486..1530, 1531..1575, 1576..1620, 1621..1665, 1666..1710, 1711..1755, 1756..1800, 1801..1845, 1846..1890, 1891..1935, 1936..1980, 1981..2025, 2026..2070, 2071..2115, 2116..2160, 2161..2205, 2206..2250, 2251..2295, 2296..2340, 2341..2385, 2386..2430, 2431..2475, 2476..2520, 2521..2565, 2566..2610, 2611..2655, 2656..2700, 2701..2745, 2746..2790, 2791..2835, 2836..2880, 2881..2925, 2926..2970, 2971..3015, 3016..3060, 3061..3105, 3106..3150, 3151..3195, 3196..3240, 3241..3285, 3286..3330, 3331..3375, 3376..3420, 3421..3465, 3466..3510, 3511..3555, 3556..3600, 3601..3645, 3646..3690, 3691..3735, 3736..3780, 3781..3825, 3826..3870, 3871..3915, 3916..3960, 3961..4005, 4006..4050, 4051..4095, 4096..4140, 4141..4185, 4186..4230, 4231..4275, 4276..4320, 4321..4365, 4366..4410, 4411..4455, 4456..4500, 4501..4545, 4546..4590, 4591..4635, 4636..4680, 4681..4725, 4726..4770, 4771..4815, 4816..4860, 4861..4905, 4906..4950, 4951..4995, 4996..5040, 5041..5085, 5086..5130, 5131..5175, 5176..5220, 5221..5265, 5266..5310, 5311..5355, 5356..5400, 5401..5445, 5446..5490, 5491..5535, 5536..5580, 5581..5625, 5626..5670, 5671..5715, 5716..5760, 5761..5805, 5806..5850, 5851..5895, 5896..5940, 5941..5985, 5986..6030, 6031..6075, 6076..6120, 6121..6165, 6166..6210, 6211..6255, 6256..6300, 6301..6345, 6346..6390, 6391..6435, 6436..6480, 6481..6525, 6526..6570, 6571..6615, 6616..6660, 6661..6705, 6706..6750, 6751..6795, 6796..6840, 6841..6885, 6886..6930, 6931..6975, 6976..7020, 7021..7065, 7066..7110, 7111..7155, 7156..7200, 7201..7245, 7246..7290, 7291..7335, 7336..7380, 7381..7425, 7426..7470, 7471..7515, 7516..7560, 7561..7605, 7606..7650, 7651..7695, 7696..7740, 7741..7785, 7786..7830, 7831..7875, 7876..7920, 7921..7965, 7966..8010, 8011..8055, 8056..8100, 8101..8145, 8146..8190, 8191..8235, 8236..8280, 8281..8325, 8326..8370, 8371..8415, 8416..8460, 8461..8505, 8506..8550, 8551..8595, 8596..8640, 8641..8685, 8686..8730, 8731..8775, 8776..8820, 8821..8865, 8866..8910, 8911..8955, 8956..9000, 9001..9045, 9046..9090, 9091..9135, 9136..9180, 9181..9225, 9226..9270, 9271..9315, 9316..9360, 9361..9405, 9406..9450, 9451..9495, 9496..9540, 9541..9585, 9586..9630, 9631..9675, 9676..9720, 9721..9765, 9766..9810, 9811..9855, 9856..9900, 9901..9945, 9946..9990, 9991..10035, 10036..10080, 10081..10125, 10126..10170, 10171..10215, 10216..10260, 10261..10305, 10306..10350, 10351..10395, 10396..10440, 10441..10485, 10486..10530, 10531..10575, 10576..10620, 10621..10665, 10666..10710, 10711..10755, 10756..10800, 10801..10845, 10846..10890, 10891..10935, 10936..10980, 10981..11025, 11026..11070, 11071..11115, 11116..11160, 11161..11205, 11206..11250, 11251..11295, 11296..11340, 11341..11385, 11386..11430, 11431..11475, 11476..11520, 11521..11565, 11566..11610, 11611..11655, 11656..11700, 11701..11745, 11746..11790, 11791..11835, 11836..11880, 11881..11925, 11926..11970, 11971..12015, 12016..12060, 12061..12105, 12106..12150, 12151..12195, 12196..12240, 12241..12285, 12286..12330, 12331..12375, 12376..12420, 12421..12465, 12466..12510, 12511..12555, 12556..12600, 12601..12645, 12646..12690, 12691..12735, 12736..12780, 12781..12825, 12826..12870, 12871..12915, 12916..12960, 12961..13005, 13006..13050, 13051..13095, 13096..13140, 13141..13185, 13186..13230, 13231..13275, 13276..13320, 13321..13365, 13366..13410, 13411..13455, 13456..13500, 13501..13545, 13546..13590, 13591..13635, 13636..13680, 13681..13725, 13726..13770, 13771..13815, 13816..13860, 13861..13905, 13906..13950, 13951..13995, 13996..14040, 14041..14085, 14086..14130, 14131..14175, 14176..14220, 14221..14265, 14266..14310, 14311..14355, 14356..14400, 14401..14445, 14446..14490, 14491..14535, 14536..14580, 14581..14625, 14626..14670, 14671..14715, 14716..14760, 14761..14805, 14806..14850, 14851..14895, 14896..14940, 14941..14985, 14986..15030, 15031..15075, 15076..15120, 15121..15165, 15166..15210, 15211..15255, 15256..15300, 15301..15345, 15346..15390, 15391..15435, 15436..15480, 15481..15525, 15526..15570, 15571..15615, 15616..15660, 15661..15705, 15706..15750, 15751..15795, 15796..15840, 15841..15885, 15886..15930, 15931..15975, 15976..16020, 16021..16065, 16066..16110, 16111..16155, 16156..16200, 16201..16245, 16246..16290, 16291..16335, 16336..16380, 16381..16425, 16426..16470, 16471..16515, 16516..16560, 16561..16605, 16606..16650, 16651..16695, 16696..16740, 16741..16785, 16786..16830, 16831..16875, 16876..16920, 16921..16965, 16966..17010, 17011..17055, 17056..17100, 17101..17145, 17146..17190, 17191..17235, 17236..17280, 17281..17325, 17326..17370, 17371..17415, 17416..17460, 17461..17505, 17506..17550, 17551..17595, 17596..17640, 17641..17685, 17686..17730, 17731..17775, 17776..17820, 17821..17865, 17866..17910, 17911..17955, 17956..18000, 18001..18045, 18046..18090, 18091..18135, 18136..18180, 18181..18225, 18226..18270, 18271..18315, 18316..18360, 18361..18405, 18406..18450, 18451..18495, 18496..18540, 18541..18585, 18586..18630, 18631..18675, 18676..18720, 18721..18765, 18766..18810, 18811..18855, 18856..18900, 18901..18945, 18946..18990, 18991..19035, 19036..19080, 19081..19125, 19126..19170, 19171..19215, 19216..19260, 19261..19305, 19306..19350, 19351..19395, 19396..19440, 19441..19485, 19486..19530, 19531..19575, 19576..19620, 19621..19665, 19666..19710, 19711..19755, 19756..19800, 19801..19845, 19846..19890, 19891..19935, 19936..19980, 19981..20025, 20026..20070, 20071..20115, 20116..20160, 20161..20205, 20206..20250, 20251..20295, 20296..20340, 20341..20385, 20386..20430, 20431..20475, 20476..20520, 20521..20565, 20566..20610, 20611..20655, 20656..20700, 20701..20745, 20746..20790, 20791..20835, 20836..20880, 20881..20925, 20926..20970, 20971..21015, 21016..21060, 21061..21105, 21106..21150, 21151..21195, 21196..21240, 21241..21285, 21286..21330, 21331..21375, 21376..21420, 21421..21465, 21466..21510, 21511..21555
|