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

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

Question 385250: You select three cards from a deck of 52 poker cards. What is the probability the cards are (in order) a Five, a Five, and a King?
Click here to see answer by Fombitz(13828)

Question 385335: hi, im so sorry for border i have been working in this problem and i cant do it, i read so many examples and i did hw about it but i cant figure out how t do it, can you help me please?? THANK YOU SO MUCH
If you were the boss, would height play a role in your selection of a successor for your job? In his Fortune column, Daniel Seligman discussed his ideas concerning height as a factor in Deng Xiaoping’s choice of Hu Yaobang as his replacement as Chairman of the Chinese Communist Party. As Seligman notes, the facts surrounding the case arouse suspicions when examined in the light of statistics.
Deng, it seemed, was only five feet tall, a height that is short even in China. Therefore, the choice of Hu Yaobang, who was also five feet tall, raised some eyebrows because, as Seligman notes, “the odds against a ‘height-blind’ decision producing a chairman as short as Deng are about 40 to 1.” In other words, if we had the relative frequency distribution of the heights of all Chinese men, only 1 in 41 (2.4%) would be 5 feet tall or shorter. To calculate these odds, Seligman notes that the Chinese equivalent of the U.S. Health Service does not exist and hence that health statistics on the current population of China are difficult to acquire. He says, however, that “it is generally held that a boy’s length at birth represents 28.6% of his final height” and that, in prerevolutionary China, the average length of a Chinese boy at birth was 18.9 inches. From this, Seligman deduces that the mean height of mature Chinese men is
(18.9)⁄(0.286)=66.08 inches, or 5 feet 6.08 inches
He then assumes that the distribution of the heights of men in China follows a normal distribution (“as it does in the U.S.”), with a mean of 66 inches and a standard deviation equal to 2.7 inches, “a figure that looks about right for that mean.
Using Seligman’s assumptions, calculate the probability that a single adult Chinese man, chosen at random, will be at most 5 feet tall.
Do the results in part 1 agree with Seligman’s odds?
Comment on the validity of Seligman’s assumptions. Are there any basic flaws in his reasoning?
Based on the results of parts 1 and 3, do you think that Deng Xiaoping took height into account in selecting his successor?

Click here to see answer by stanbon(57347)

Question 385256: To test the hypothesis that students who finish an exam first get better grades, Professor Hardtack
kept track of the order in which papers were handed in. The first 25 papers showed a mean score of
77.1 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 a significant difference at α = .05? (a) State the
hypotheses for a right-tailed test. (b) Obtain a test statistic and p-value assuming equal variances.
Interpret these results. (c) Is the difference in mean scores large enough to be important? (d) Is it reasonable
to assume equal variances? (e) Carry out a formal test for equal variances at α = .05, showing
all steps clearly.
Click here to see answer by stanbon(57347)

Question 385380: a box of colored thumb tacks contains 80 tacks, with an equal assortment of red, green, blue, and yellow tacks. if you close your eyes and select a single thumb tack , what is the probability that it will not be red?
Click here to see answer by stanbon(57347)

Question 385324: find the probablity of getting a prime number in each of the following cases:
a) a number is chosen randomly from the set {1,2,3,4,5,6,7,8,9,10 and 11}
b)two dice are rolled and the sum is observed.
Click here to see answer by Fombitz(13828)

Question 385417: In how many ways can you select 2 kings and an ace, in that order, from a standard deck of 52 cards?
Click here to see answer by stanbon(57347)

Question 385406: What is the formula needed to solve:
How many ways can six books be arranged on a shelf if one book is a novel that must be on the end?
Click here to see answer by edjones(7569)

Question 385373: At an urban hospital, the weights of all newborns are recorded. Over the last 10 years, the daily rate has been in excess of 50 births per day. The mean and stdev of weights for all recorded newborns is shown below. What is the probability that:
Pounds
m 7.125
stdev 0.125
a. A baby born today will weigh 8 pounds or more?
z(8) = (9-7.125)/0.125 = 15
Question: Why is 9 used instead of the z score 8? When I use 8 I end up with the probabiliy of 1. Also, would 15 be the answer to the probability or am I missing a step?
Thank you,

Click here to see answer by stanbon(57347)

Question 385495: In Dallas, some fire trucks were painted yellow (instead of red) to heighten their visibility. During
a test period, the fleet of red fire trucks made 153,348 runs and had 20 accidents, while the fleet of
yellow fire trucks made 135,035 runs and had 4 accidents. At α = .01, did the yellow fire trucks
have a significantly lower accident rate? (a) State the hypotheses. (b) State the decision rule and
sketch it. (c) Find the sample proportions and z test statistic. (d) Make a decision. (e) Find the
p-value and interpret it. (f ) If statistically significant, do you think the difference is large enough to
be important? If so, to whom, and why? (g) Is the normality assumption fulfilled? Explain.
My question is...I don't know where to start. How do I know what formula to use? To find the z value, excel wants variable ranges. ?? How do I find the sample proportions?
I am in a crunch situation and need the answers, but I also want to know how to do the problems.
Thanks

Click here to see answer by stanbon(57347)

Question 385489: A card is selected from a deck of 52 playing cards. Find the probability of selecting

· an even number ten or less given the card is a not a diamond.
· an Ace, given that the card is black.
· a spade given the card is red.

Click here to see answer by Edwin McCravy(8909)

Question 385625: In how many different ways can the top twelve new indie bands be ranked on a top twelve list? The top hit song for each of the twelve bands will compete to receive monetary awards of $1000, $500, $250 and $100, respectively. In how many ways can the awards be given out?

Click here to see answer by stanbon(57347)

Question 385634: a coin is flipped five times. find the number of possible sets of heads and tails that have each of the follwing
a. 0 heads
b. 2 heads
Click here to see answer by stanbon(57347)

Question 385745: A set of final examination grades in an introductory statistics course was founded to be normally distributed with a mean of 73 and a standard deviation of 8.
a. what is the probability of getting at most a grade of 91 on the exam?
b. what percentage of students scored between 65 and 85?
c. what percentage of students scored between81 and 89?
d. what is the final exam grade in only 5% of the students taking the test scored higher?
e. If the professor "curves"( gives A`s to the top 10% of the class regardless of the score), are you better off with a grade of 81on this exam or a grade of 68 on a different exam where the mean is 62 and the standard deviation is 3? show statistically and explain
Include a normal distribution curve
Click here to see answer by stanbon(57347)

Question 385490: Consider the following contingency table of travelers on a cruise ship and their ages:

Age 1st cruise 2nd cruise 3rd cruise
21 - 30 25 17 33
31 - 40 12 23 10
41 – 50 35 15 45
Total 72 55 88
A. If a person is selected at random, what is the probability it is his/her 2nd cruise? ____

B. If a person is selected at random, what is the probability the person is either in the age group 31-40 or 41-50? ____

C. If a person is selected at random, what is the probability the person is either 21-30 or on his/her 2nd cruise? _____

D. If two people are selected at random, what is the probability they are both on their 1st cruise? ____
If I get this answer correct, I will provide you with a DONATION.
Click here to see answer by stanbon(57347)

Question 385961: 500 articles were selected at random out of a batch containing 10000 articles,and 30 are found defective.how many defective articles would you reasonably expect to have in the whole batch?
Click here to see answer by mtmorro(23)

Question 386016: you are going to select 2 cards from a standard deck (without replacement). What is the probability that you will select 2 kings? (Round to 4 decimal places).
Click here to see answer by Fombitz(13828)

Question 386067: A statistical study is being conducted to determine if the population mean yield for all Arizona municipal bonds is greater than the national average. A random sample of size (n=16) is drawn from Arizona municipal bonds. What would be the critical value (a=.01) for this test?
Click here to see answer by stanbon(57347)

Question 386069: Sixty-two balls numbered from 1 to 62 are placed in an urn. One ball is randomly drawn from the urn. What is the probability that the number on the ball is greater than or equal to 24?
Click here to see answer by stanbon(57347)

Question 386070: Please help me with this homework problem:
What is the standard error of mean for these three appraisal values: 215,195, and 160?
I said 27.84 for my answer. I came up with this by take s/ the square root of n. Is this correct?
Click here to see answer by stanbon(57347)

Question 386071: A veterinarian tells you that the mean life span of an Appaloosa horse is 19 years with a standard deviation of 2 years. Use Chebyshev's Theorem to find an interval A to B for the number of years in which at least 93.8% of the Appaloosa life spans will fall.
Click here to see answer by stanbon(57347)

Question 386073: A weighted coin is tossed four times. The probability for the number if heads observed is given below
# heads Probability
0 .4096
1 .4096
2 .1536
3 .0256
4 .0016

What is the probability of getting at least ones head?
Click here to see answer by stanbon(57347)

Question 386068: The lifetime of a Duracell AAA battery is normally distributed with a mean M=28.5 hours and standard deviation baby sigma= 5.3 hours. Compute z scores to determine for a battery selected at random, what is the probability is that the lifetime will be
a.) 25 hours or less
b.) 34 hours or more
c.) between 25 hours and 34 hours.
Click here to see answer by stanbon(57347)

Question 386078: Please help with these homework questions:
A special diet should reduce cholesterol below 200. An SRS of 50 patients at risk had an average cholesterol of -x(mean)=192, with standard deviation s=21. Is this sufficient evidence that the diet is effective? Assume the distribution of the cholesterol for patients is approximately normal with mean u.
1)What is an appropriate hypothesis?
I said that the appropriate hypothesis is
Ho: u= 200, Ha: u> 200.
Is this hypothesis correct?
2)The appropriate degrees of freedom for this test are:
I said 51 by using f = [ s12/σ12 ] / [ s22/σ22 ]
Is this correct?
3)Based on the data, one sample t-statistic is?
I said 2.89 by using 200-192/21 x square root of (50/50-1)
Is this correct?

Click here to see answer by stanbon(57347)

Question 386085: The average monthly gasoline purchase for a family with 2 cars is 85 gallons. This statistic has a normal distribution with a standard deviation of 12 gallons. A family with 2 cars is chosen at random.
(a) Find the probability that the family’s monthly gasoline purchases will be between 80 and 90 gallons.
(b) Find the probability that the family’s monthly gasoline purchases will be less than 75 gallons.
(c) Find the probability that the family’s monthly gasoline purchases will be more than 90 gallons
Click here to see answer by stanbon(57347)

Question 386083: The probability that a house in an urban area will be burglarized is 8.5%. If 45 houses are randomly selected, what is the probability that four of the houses will be burglarized?
(a) Is this a binomial experiment? Explain how you know.
(b) Use the correct formula to find the probability that, out of 45 houses, exactly 4 of the houses will be burglarized. Show your calculations or explain how you found the probability
Click here to see answer by stanbon(57347)

Question 386124: If two fair dice are rolled, what is the probability that a total of three shows?

Click here to see answer by fantastic(2)

Question 386163: If we are interested in determining how many different slates of officers (chairman, vice-chairman, and secretary) we can pick from a committee of five, would we apply the combination formula or the permutation formula? Explain. ( you don't have to actually do the computation).
Click here to see answer by solver91311(16885)

Question 386179: Suppose 3 cards are randomly chosen (without replacement) fron an ordinary deck of 52 playing cards, and order desn't matter.

a. calculate the size of the sample space.

b. calculate the size of the event "all three cards drawn are aces", You can do this by listing all the ways, then counting them up; or by using combinations.

c.If the above results to calculate the probability of drawing three aces. Express the answer as a fracrtion reduced to simpllest terms.

Click here to see answer by ewatrrr(10682)

Question 386178: Please help me answer this question.
A random sample of 121 men regarding IQ scores produced a mean of 104 points with a standard deviation 16 points. Construct a 98% confidence interval for the mean number of IQ scores.
Click here to see answer by ewatrrr(10682)

Question 386229: A 20-minute Oil and Lube service claims that their average service time is no more than 20 minutes. A random sample of 40 service times was collected, and the sample mean was found to be 21.3 minutes, with a sample standard deviation of 5.5 minutes. Is there evidence to reject the claim at the alpha = 0.05 level? Perform an appropriate hypothesis test, showing the necessary calculations and/or explaining the process used to obtain the results.
Click here to see answer by stanbon(57347)

Question 385986: Julie's ice cream parlour has scoops of two sizes. Each scoop produces a spherical portion of ice
cream. The smaller scoop has a radius of 1 inch, while the larger scoop has a radius of 1.5 inches.
What is the ratio of the volume of a large scoop to the volume of a small scoop?
Click here to see answer by scott8148(6628)

Question 386270: the telephone extensions at a company use 4 digits
a. how many extensions are possible if there are no restrictions?
b. how many extensions are possible if the first digit cannot be 0 or 9?
c. how many extensions are possible if the first digit can only be 1?
Click here to see answer by stanbon(57347)

Question 386324: A bag contains 4 white, 6 green, and 8 yellow chips. What is the probability that a randomly selected chip will be white or yellow?
Click here to see answer by chiggypiggy(2)

Question 386341: show all work. twenty percent of american households own three or more cars. a random of 100 american households is selected. let x be the number of households selected that own three or more cars
the probability that at least 30 of the households selected own at least 3 or more cards is
Click here to see answer by stanbon(57347)

Question 386351: a box has 2 red chips, 2 blue chips. and 1 green chip. 2 chips are randomly selected together. what is the probability of selecting 2 blue chips.
Click here to see answer by chiggypiggy(2)

Question 386357: show all work. in an instant lottery, your chances of winning are .2. if you play the lottery five times and outcomes are independent, the probability that you win at most once is
Click here to see answer by robertb(4012)

Question 386432: The password to gain entrance to a company is a sequence of 5 letters chosen from A to K. If a letter can be repeated, how many different passwords can be made?
Click here to see answer by robertb(4012)

Question 386325: What is the probability of rolling a sum less than 5 or greater than 10 when tossing two dice?
Click here to see answer by rajagopalan(158)

Question 386363: an experiment consist of tossing two ordinary dice and adding the two numbers. determine the probability of obtaining a sum less than or equal to 4.
Click here to see answer by Fombitz(13828)

Question 386379: a and b take turns cutting a pack of 52 cards and the pack is shuffled after each cut. if a starts and the cards are cut until one cuts a diamond, whet are the respective chances of a and b first cutting a diamond?
Click here to see answer by Fombitz(13828)

Question 386490: Which pair has equally likely outcomes? List the letters of the two choices below which have equal probabilities of success, seperated by a comma. A standard deck of cards has 12 face cards and four aces (aces are not face cards). Please show your probability for each choice below.
a) drawing a red five out of a standard 52 card deck given it's not a face card or an ace.
b) rolling a sum of 10 on two fair six sided dice.
c) rolling a sum of 3 on two fair six sided dice.
d) rolling a sum of 7 on two fair six sided dice.
e) drawing a four out of a standard 52 card deck given it's not a face card or an ace.
Click here to see answer by ewatrrr(10682)

Question 385979: What of the following will produce a large value for the chi-square statistic?
there is a good fit between the sample data (observed values) and the null hypothesis the observed values from the sample data are consistently larger than the expected values the observed values from the sample data are consistently smaller than the expected values the sample data (observed values) do not fit the null hypothesis
Click here to see answer by stanbon(57347)

Question 386535: If 20 people where selected at random, what is the probability that exactly 12 of those people have brown eyes?
Click here to see answer by solver91311(16885)

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