Questions on Algebra: Probability and statistics answered by real tutors!

Tutors Answer Your Questions about Probability-and-statistics (FREE)

Question 618179: 2. Find the area under the standard normal curve:
I. to the right of z = 1.27
II. to the left of z = 1.27
Click here to see answer by stanbon(57203)

Question 618252: Find P(rolling 2 or 5) with one number cube.
Click here to see answer by richard1234(5390)

Question 618340: Suppose we have a set of body temperatures with a mean of 98.6 degrees, and a sample standard deviation of 0.5 degrees. If we assume a normal distribution of body temperatures in the larger population, between what two values should 99.7% of all temperatures lie?
Click here to see answer by ewatrrr(10682)

Question 618318: A normal population has μ = 30 and σ = 7. For a random sample of size n = 6, determine the mean of X and
standard deviation of X.
Click here to see answer by ewatrrr(10682)

Question 618336: Forty-five percent of the adults in a particular large city are women. A court is to randomly select a jury of 12 adults from the population of all adults of the city

(a) Find the probability that none of the 12 jurors are a women
(b) Find the probability that at most 4 of the 12 jurors are women
A mail order company receives all average of 40 orders per day.
(i) Find the probability that it will received exactly 55 orders on a certain day.
(ii) Find the probability that it will receive at most 29 orders on a certain day.
Assume that the distribution of time spent on leisure activities by certain employed adults living in household with no children younger than 18 is normally distributed with mean of 4.4 hours per day and the standard deviation of 1.08 hour per day.
Find the probability that the amount of time spent on leisure activities per day for a randomly selected person from the population of interest is
(a) More than 7.2 hours per day
(b) 4.2 to 6.5 hours per day
(c) Less than 6 hours per day
(d) More than 24 hours per day
(e) How much time must be spent on leisure activity by an employed adult living in household with no children younger than 18 years to be in the group of such adults who spend the highest 3.5% of the time in a day in such activities
Create 150 samples, each containing the result of 35 numbers from 1 through 100. Calculate the means of these 100 samples. Construct the Histogram and calculate the mean and standard deviation of these sample means.

A particular industrial product has shipped in lots of 20. Testing to determine whether an item is defective is costly; hence the manufacture samples production rather than using 100% inspection plan. A sampling plan constructed to minimize the number of defectives shipped to customers call for sampling fine items form each lot and reject the lot if more than one defect is observed.
(a) What is the probability that the lot will be rejected
(b) What is the probability that the lost will not be rejected

Click here to see answer by solver91311(16868)

Question 618427: Eric guesses at all 10 true/false questions on the multiple choice section in his recent math test. Find the probability of getting at least half correct.
Click here to see answer by ewatrrr(10682)

Question 249686: A bag contains 7 lavender marbles, 11 turquoise marbles and 5 rainbow marbles. What is the chance of drawing a rainbow marble? If a rainbow marble is drawn then placed back into the bag, and a second marble is drawn, what is the probability of drawing a lavender marble? Thanks!
Click here to see answer by ahodges2105(4)

Question 618169: 84% of the students who complete this class receive a passing grade. in a class of 64 how many will pass?
Click here to see answer by ahodges2105(4)

Question 618032: What is the probability of this event? P(4)
Click here to see answer by richard1234(5390)

Question 618569: what's the probability of getting 3 of the last 5 questions right out of 25 questions when I know 20 answers total?
Click here to see answer by stanbon(57203)

Question 618563: I have 1000 completely independent events E1, E2, E3... E1000 that each have a 5% chance of occurring any given day.
1. How can I predict with say 90% confidence how many events occur on any given day?
2. What is the probability that at least 100 items occur on a given day?
Could you please explain the solution too?
Thanks!
Click here to see answer by stanbon(57203)

Question 618588: A class consists of 92 women and 39 men. If a student is randomly selected, what is the probability that the student is a woman?
Click here to see answer by John10(245)

Question 618582: Please help me solve this: A school survey shows that 10% of students are in band, 12% of students are in athletics, and 6% of students are in both band and athletics. What is the probability that a student is in band or athletics?
Click here to see answer by John10(245)

Question 618653: Find the odds in favor of the event whose probability is given in the problem.
P(E)= 1/4
Click here to see answer by ewatrrr(10682)

Question 618643: Find the number of possible 7 card hands that contain 3 hearts and 4 black cards. The cards are taken from a standard 52 card deck
answer: 13C3 x 26C4
Five cards are drawn from a standard deck of 52 cards. Find the probability of 2 Aces and 3 Fives.
answer: 4C2 x 4C3 divided by 52C5
My question is why is the first one just C's and the second is divided??I do not understand why there is a difference in solving the two questions. Please help my test is tommarrow an I want to know why they are solved differently. Thanks
Click here to see answer by scott8148(6628)

Question 618723: The probability that Susan does not hand in her maths homework on time is 0.52. If susan has been given 25 homeworks in one term how many homeworks would you expect her to hand in?

Click here to see answer by ewatrrr(10682)

Question 618748: In an effort to check the quality of their cell phones, a manufacturing manager decides to take a random sample of 10 cell phones from yesterday’s production run of 2000 phones. If each of the 2000 phones is likely to be selected:
i)What is the probability that a randomly selected cell phone will be one of the last 80 produced?
ii)What is the probability that the first cell phone selected is either from the last 160 produced or from the first 90 to be produced?
iii)What is the probability that the first two cell phones are both from the last 80 produced?

Click here to see answer by stanbon(57203)

Question 618758: A bookshelf has 4 non-fiction books, 6 fiction books, and 2 dictionaries.
Two books are randomly selected, with replacement. Find the probability of choosing a fiction book, and then selecting a dictionary.
Click here to see answer by ewatrrr(10682)

Question 618770: The time required to finish a test in normally distributed with a mean of 80 minutes and a standard
deviation of 15 minutes. What is the probability that a student chosen at random will finish the test in more
than 110 minutes?
Click here to see answer by ewatrrr(10682)

Question 618774: a coin is tossed and then a die is rolled find the probability that the coin shows heads and the die shows a number less than five
Click here to see answer by nerdybill(6948)

Question 618777: Shari has twelve cards, numbered from one to twelve. She randomly draws three cards with replacement. What is the probability that Shari draws an even card then two odd cards?
Click here to see answer by ewatrrr(10682)

Question 618925: A realty company has 100 homes listed for sale.Some of these homes have fire places, some have garages, and some have neither.
Garage and Fireplace 50
Garage with no fireplace 30
No Garage and fireplace 10
No garage and no fireplace 10
What is the probabiltiy that the home selected has a fireplace or a garage?
Click here to see answer by richwmiller(9132)

Question 618667: If d mean of seven number is 96 and an eighth number is added which makes the number becomes 112. What wil b dat eighth number?
Click here to see answer by stanbon(57203)

Question 618813: Your chemistry professor is to assign grades of A, B, C, D, or F in a class of 250 students. How many different grade distributions (total number of A's, B's, C's, D's, and F's; For example, 40 A's, 75 B's, 90 C's, 40 D's, and 5 F's) are possible?
The answer is 169,362,501. I am unsure as to how to arrive to this answer. Looking at a solution to it, they used a combinatorial of picking 4 from a pool of 250. --> C(250+4,4) ....But, it does not explain why.
Please Help, thank you.
Click here to see answer by Edwin McCravy(8879)

Question 619012: a true-false test has 4 questions. what is the chance that all alswers are true? express your answer as a percent
Click here to see answer by solver91311(16868)

Question 618949: The mean time taken by all participants to run a road race was found to be 220 minutes with a standard deviation of 20 minutes. Using the 68 – 95 – 99.7 Rule, find the percentage of runners who ran this race:
a. In less than 180 minutes
b. In more than 220 minutes
c. In between 160 and 280 minutes
d. In at least 240 minutes
e. In no more than 200 minutes
Click here to see answer by ewatrrr(10682)

Question 619059: a two-tailed test is conducted at the 5% significance level. What is the right tail percentile required to reject the null hypothesis?
Click here to see answer by ewatrrr(10682)

Question 618998: Mobile homes are tightly constructed for energy conservation. This can lead to a buildup of indoor pollutants. The paper "A Survey of Nitrogen Dioxide Levels Inside Mobile Homes" discussed various aspects of NO2 concentration in these structures.
(a) In one sample of mobile homes in the Los Angeles area, the mean NO2 concentration in kitchens during the summer was 36.66 ppb, and the standard deviation was 11.44. Making no assumptions about the shape of the NO2 distribution, what can be said about the percentage of observations between 13.78 and 59.54? (Round the answer to the nearest whole number.)
At least
%
(b) Inside what interval is it guaranteed that at least 89% of the concentration observations will lie?

,

Click here to see answer by stanbon(57203)

Question 618935: Find the standard score (z) such that the area above the mean and below z is about 34% of the area under the normal curve
Click here to see answer by stanbon(57203)

Question 618875: You roll 2 dice. What is the probability that the sum of the dice is odd and both dice show the number 3?  Write fractions using the slash ( / ) key. Reduce fractions to their lowest terms.
Click here to see answer by stanbon(57203)

Question 619075: The probability that you will invest in a stock which appreciates, or is a “good” stock is 1 in 10. Find the probability that your 6th stock is your 3rd good stock?
I dont know where to start. Please helpppp
Click here to see answer by stanbon(57203)

Question 618811: Let Z by a standard normal random variable. Solve for c.
P(c≤Z≤0.57)=0.6907
Click here to see answer by stanbon(57203)

Question 619114: what is p(0.84 < z < 1.26)=
Click here to see answer by user_dude2008(1861)

Question 619164: a rupee coin is tossed 10 times what is the probability that head will appear exactly 7times.
Click here to see answer by Edwin McCravy(8879)

Question 619226: I'm not sure if I'm understanding this problem. Can anyone provide a step-by-step explanation?
Given a binomial distribution with n = 22 and p = 0.78, would the normal distribution provide a reasonable approximation? Why or why not?
Click here to see answer by Theo(3458)

Question 619237: Just over half (0.6) of the homes built in the new upper-bracket snootyville subdivision included a room designed specifically to be a home theater. Four snootyville homes are selected at random.
what is the chance that all four homes will have the home theater room?
What is the chance that non of the homes in the sample of four will have the home theater room?
Click here to see answer by Theo(3458)

Question 619269: A box contains 12 large marbles and 20 small marbles. Each marble is either green or white. 6 large marbles are green and 3 of the small marbles are white. WHat is the probability that it is small or white?
Click here to see answer by stanbon(57203)

Question 619285: Find the area under the standard normal curve for the following:
(A) P(z > 2.15)
(B) P(-1.79 < z < 0)
(C) P(-1.71 < z < 1.13)

Click here to see answer by stanbon(57203)

Question 619249: Whats the probability that if you draw 2 marbles without replacement out of a bag containing 1 green, 2 yellow, and 3 red, that both of them are red?
Click here to see answer by stanbon(57203)

Question 619301: A 5-card hand is dealt from a deck of 52 cards. What is the probability that exactly one card is a king?
Click here to see answer by sophxmai(60)

Question 619298: A 5-card hand is dealt from a deck of 52 cards. What is the probability that
a.) none are queens?
b.) all are queens?
Click here to see answer by sophxmai(60)

Question 619298: A 5-card hand is dealt from a deck of 52 cards. What is the probability that
a.) none are queens?
b.) all are queens?
Click here to see answer by richard1234(5390)

Question 619296: If 11 coins are tossed what is the probability of getting EXACTLY 2 heads?
Click here to see answer by sophxmai(60)

Question 618442: Is there a significant difference in the mean height between the Eastern and Western Conference National Basketball League players? Provide the IV, DV, and best method of analysis.
Click here to see answer by richard1234(5390)

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