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

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

Question 623665: How many different 4 letter radio station call letters can be made if the first letter must be K or W, repeats are allowed, but the call letters cannot end in an O? please explain.
Click here to see answer by jsmallt9(3296)

Question 623684: Give one reason why the natural numbers {1,2,3,4,5,....} are not a group under addition. please explain
Click here to see answer by jim_thompson5910(28549)

Question 623717: Of 78 people who answered "yes" to a question, 20 were male. Of the 72 people who answered "no" to the question, 19 were male.
If one person is selected at random from the group, what is the probability that the person either answered "yes" or was male?

Click here to see answer by solver91311(16877)

Question 623744: Five balls are selected at random without replacement from an urn containing three white balls and five blue balls. Find the probability of the given event. (Round your answer to three decimal places.)
Two or three of the balls are white.
Click here to see answer by edjones(7569)

Question 623743: The Odds against A solving a problem in statistics are 10 to 8; the odds in favour of B and C solving the same problem 12 to 9 and 15 to 10 respectively. What are the probabilities that the problem will be solved and all three will solve the problem
Click here to see answer by edjones(7569)

Question 623802: A distribution has a standard deviation of 12.
Find the z-score for each of the following locations in
the distribution.
a. Above the mean by 3 points.
b. Above the mean by 12 points.
c. Below the mean by 24 points.
d. Below the mean by 18 points.
I understand that z= (data point- mean)/standard deviation.
What I got so far for a. is...
100(because z-scores=100)= x-3/12
Do I solve for x and that is the answer?
Click here to see answer by ewatrrr(10682)

Question 623932: If I have 16 smokers out of a possible 63 and I choose 3 people at random from the 63 what is the probability that exactly 2 of them will be smokers?
Click here to see answer by ewatrrr(10682)

Question 624015: I am having trouble understanding "at most" and "at least"
If, for example, the problem was " ... Their times are normally distributed with a mean of 184 minutes and a standard deviation of 55 minutes. For a randomly selected person from the control group, find the probability that the time is at least 210 minutes."
I used the following function on my TI-84:
2ND, VARS, normalcdf(209.5,1E99,184,55)
=0.321454
=32.14%
is this correct?
Thanks for your time.
Click here to see answer by ewatrrr(10682)

Question 624222: If a coin is tossed two thousand times, what is the probability that all the heads appear between 900 to 1100th toss.
Click here to see answer by Alan3354(30993)

Question 624271: By measuring the amount of time it takes a component of a product to move from one workstation to the next, an engineer has estimated that the standard deviation is 3.09 seconds.

(A) How many measurements should be made in order to be 95% certain that the maximum error of estimation will not exceed 1.5 seconds?

(B) What sample size is required for a maximum error of 0.5 seconds?

Click here to see answer by ewatrrr(10682)

Question 624275: A confidence interval estimate for the population mean is given to be (40.21, 48.95). If the standard deviation is 13.394 and the sample size is 51, answer each of the following (show all work):

(A) Determine the maximum error of the estimate, E.

(B) Determine the confidence level used for the given confidence interval.

Click here to see answer by ewatrrr(10682)

Question 624272: A 98% confidence interval estimate for a population mean was computed to be (45.9, 60.5). Determine the mean of the sample, which was used to determine the interval estimate (show all work).
Click here to see answer by ewatrrr(10682)

Question 624282: Lotto Texas select the six winning numbers from 1,2...,54
Click here to see answer by Alan3354(30993)

Question 624285: Florida fantasy select the five winning numbers from 1,2...,36
Click here to see answer by Alan3354(30993)

Question 624305: how do you use a table to determine the binomial probability for n=10, x=6. and p=0.6
Click here to see answer by richard1234(5390)

Question 624428: The time required for the credit card application process follows a normal distribution with a mean of 10 days and a standard deviation of 4 days. Find the probability that the time taken to process a particular credit card application
(a) exceeds 13 days
(b) is less than 5 days
Please help me to solve this problem for me.
Click here to see answer by Emsley(35)

Question 624406: Please show me specific detailed answers to these question i got wrong on my test. Thankyou.
An internal survey of a company showed that their staff needs to spend about 55 minutes from home to work every morning on average. It was also reported that 3% of the staff needs over two hours for the travel.
(i) If 50 staff is surveyed on a particular day, what is the probability that 5 will report the travel of over two hours?
(ii) If the company has 3000 staff, what is the expected number of staff who has the travel of over two hours?
(iii) If the company has 3000 staff, what are the variance and standard deviation of the number of staff who has the travel of over two hours?

Click here to see answer by Theo(3458)

Question 624479: Consider a couple having four children. We will consider this to be a binomial experiment with the number of trials n equal to 4. Let us assume that success will mean a girl is born, and failure will mean a boy is born (don’t take it personally, guys). The probability of success in any trial, then, is ½, or 0.5.
Write down the formula that gives the probability of Xsuccesses in the 4 trials in this binomial experiment. Simplify as much as possible.

Use your formula to fill in a probability distribution table for X. It should look familiar!

X p(X)

Compute E(X), doing as little work as is needed. Again, your answer should look familiar.

Click here to see answer by richard1234(5390)

Question 624539: If you had 13 toppings how many different 4 topping pizzas can you make
Click here to see answer by jim_thompson5910(28549)

Question 624546: One environmental group did a study of recycling habits. It found that 74% of aluminum cans were recycled. If 392 cans are recycled what is the probability that 300 or more are cycled. I get .1151 using u=np=290.08 and O = 8.68 with the approximation method (>300.5) The next part is: what is the probability of 260-300. Same process gets me .8849. It's wrong but I don't know why.
Help is appreciated.
Thanks
Click here to see answer by Edwin McCravy(8906)

Question 624542: According to popular belief, 81% of adults enjoy drinking beer. Choose a group of 3 adults at random. The probability that none of them enjoy drinking beer is

Click here to see answer by Calmatsar(1)

Question 624708: The odds against Lounging Larry winning the horse race are 8:5. Determine the probability that Lounging Larry wins the horse race.

Click here to see answer by solver91311(16877)

Question 624732: I need some much needed assistance with this. Can someone help?....
A researcher claims that the average age of people who buy lottery tickets is 61. A sample of 30 is selected and their ages are recorded as shown below. The standard deviation is 8. At a
= 0.01 is there enough evidence to reject the researcher’s claim? Show all work.
49
63
66
52
25
80
72
56
33
56

51
46
70
74
70
61
65
71
28
74

79
76
35
49
62
68
54
67
69
45

Click here to see answer by ewatrrr(10682)

Question 624633: Overall, the amount of work-hours involved in the festival preparation is normally distributed around 80 hours with a standard deviation of 8 hours.
a) What’s the probability that the mean number of work-hours will be between 85 and 90?
b) The members at or below the 10%ile of number of worked-hours must attend a one-on-one meeting with their supervisor. At least how many work-hours you should have in order to avoid attending such session?
c) How likely (what is the probability) is it to have the number of involved work-hours below 80?
d) How likely (what is the probability) is it to have the number of involved work-hours below 65?
e) How likely (what is the probability) is it that some employee will have his/her involved work- hours between 73 and 88?

Click here to see answer by ewatrrr(10682)

Question 624759: Suppose Nate wins 91% of all starring contests,(a) what is the probability of nate winning two starring contests in a row, (b) what is the probability of nate winning six starring contests in a row?
Click here to see answer by solver91311(16877)

Question 624806: why is there variation in the number of raisins in acup of raisin bran?
Click here to see answer by richard1234(5390)

Question 624830: A jury pool consists of 25 people. How many different juries consisting of 12 people are possible?
Click here to see answer by reynard2007(52)

Question 624858: A box contains 4 red, 4 white and 5 green balls.Three balls are drawn from the box together. Find the probability that they may be all of different colours?
Click here to see answer by oscargut(891)

Question 624886: a company ships computer components in boxes that contain 20 items. Assume that the probablity of a defective computer components is 0.2.Use the geometric variance to find the variance of defective parts.
Click here to see answer by Edwin McCravy(8906)

Question 624879: if a person rolls doubles when tossing two dice, the roller profits $95. If the game is fair, how much should the person pay to play the game?
Click here to see answer by Edwin McCravy(8906)

Question 624883: according to police sources, a car with a certain protection system will be recovered 87% of the time. Find the probablity that 4 of 8 stolen cars will be recovered.
Click here to see answer by ewatrrr(10682)

Question 624881: in one city, 21% of adults smoke. in groups of size 130 adults, what is the variance of the number that smoke?
Click here to see answer by oscargut(891)

Question 624967:
Click here to see answer by user_dude2008(1861)

Question 625051: Suppose that a pharmacy wants to estimate the standard deviation of the daily demand for a certain drug. It is known that the daily demand for this drug follows an approximately normal distribution. A random sample of 26 days has a sample mean of 125 orders for this drug with a standard deviation of 10 orders. Find a 90% confidence interval for the population standard deviation of the daily demand for this antibiotic.
What is the lower limit of the 90% confidence interval?
What is the upper limit of the 90% confidence interval?
I'm pretty lost with statistics and am looking for a tutor I can understand, but any help would be appreciated. Thank you in advance!
Click here to see answer by oscargut(891)

Question 625104: 12 Experiments will be run. It will use 4 different temperatures 3 times, with each temperature being run in random order. In how many orders can the series of experiments be ran?
Click here to see answer by oscargut(891)

Question 625108: A computer has 16 ports and at any given time ports are either in use or not in use. How many possibilities for total port usage? How many of these entail the use of at least one port?
Click here to see answer by oscargut(891)

Question 625107: There are 10 people on a staff. 4 are women and 6 are men all are equally qualified. In a random selection of three workers, what is the probability that no women will be selected? Would you consider no women being selected under these conditions unusual?
Click here to see answer by oscargut(891)

Question 625115: A locker contains eight books. You select three books at random. Classify the situation as permutation or combination
Click here to see answer by oscargut(891)

Question 625149: AFter completing an exam you find that the standard deviation is equal to -2.33. It is reasonable to assume that
A. A mistake has been made
B the average value is zero
c the variance is negative
d all observations are the same value
Click here to see answer by oscargut(891)

Question 625156: Suppose a jar contains 19 red marbles and 34 blue marbles. If you reach in the jar and pull out 2 marbles at random, find the probability that both are red.

Click here to see answer by oscargut(891)

Question 625167: If a jury consists of 10 men and 15 women, what is the probability of selecting a 6-person jury consisting of all females?
Click here to see answer by oscargut(891)

Question 625167: If a jury consists of 10 men and 15 women, what is the probability of selecting a 6-person jury consisting of all females?
Click here to see answer by nerdybill(6958)

Question 625168: Use Chebyshev’s theorem to find what percent of the values will fall between 175 and 241 for a data set with a mean of 208 and standard deviation of 11.
Use the Empirical Rule to find what two values 99.7% of the data will fall between for a data set with a mean of 245 and standard deviation of 16.

Click here to see answer by oscargut(891)

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