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

Question 629648: Estimate the probability of getting a baby girl in at least 8 of 15 births.
Click here to see answer by richard1234(5390)

Question 630570: A biased six-sided die has one face bearing number 3, two faces number 2 and three faces number 1. A boy tosses the die once and observes the number on the uppermost face. He then tosses a number of fair coins equal to the number shown on the die. The random variable X is the number of heads obtained.
Construct the probability density function of X.
Click here to see answer by Edwin McCravy(8908)

Question 630623: How many different ways can 4 women and 7 men be selected from
11 married couples (assuming no gay marriages).
Click here to see answer by Edwin McCravy(8908)

Question 630640: A sample of data has a standard deviation of 10. If you were to multiply all of the scores in the data set by factor of nine (9), what would the new standard deviation be?

Click here to see answer by stanbon(57307)

Question 630638: A regression analysis between sales (Y) and advertising (X) (both in dollars) resulted in the following equation:
= 100 + 2000X
The above equation implies that an
Answer
A. increase of $1 in advertising is correlated with an increase of $2,000 in sales.
B. increase of $1 in advertising is correlated with an increase of $2 in sales.
C. increase of $1 in advertising is correlated with an increase of $100 in sales.
D. increase of $1 in advertising is correlated with an increase of $2100 in sales.

Click here to see answer by stanbon(57307)

Question 630750: There are 2 roads from City A to City B and 4 roads from City B to City C. How many different routes are there from City A to City C, passing through City B?
Click here to see answer by stanbon(57307)

Question 630712: It is determined that the 100 subjects have a sample mean serum cholesterol level of 217 and the sample standard deviation is 39. If the desirable serum cholesterol level is set at 200, would you have concerns about elevated serum cholesterol level in this sample? Use a = .05
Click here to see answer by stanbon(57307)

Question 630710: A researcher wanted to determine whether a program for routine cholesterol screening for college men
would identify high serum cholesterol levels. The researcher decided that above 200 would be high. Twenty
students were randomly selected for cholesterol screening, and the results were given below. Is there any
evidence that asymptomatic college men have elevated serum cholesterol values? Would a large-scale screening program be warranted? Use a = 0.05
160 210 200 230 210 150 220 190 210 220
160 220 240 180 200 200 210 170 180 220
Click here to see answer by stanbon(57307)

Question 630763: An automobile assembly line operation has a scheduled mean completion time,u, of 13.7 minutes. The standard deviation of completion times is 1.7 minutes. It is claimed that, under new management, the mean completion time has decreased. To test this claim, a random sample of 19 completion times under new management was taken. The sample had a mean of 13.4 minutes. Assume that the population is normally distributed. Can we support, at the 0.05 level of significance, the claim that the mean completion time has decreased under new management? Assume that the standard deviation of completion times has not changed.
Perform a one-tailed test.
Null hypothesis: ?
Alternative hypothesis: ?
Type of test statistic: ?
The value of the test statistic: ?
The p-value: ?
Can we support the claim that the mean completion time has decreased under new management?
Click here to see answer by reviewermath(514)

Question 630702: An estimate of the population mean based on a large sample is less reliable than an estimate made using a small sample. true/false
Click here to see answer by stanbon(57307)

Question 630769: Each month the National Association of Purchasing Managers publishes the NAPM index. One of the questions asked on the survey to purchasing agents is: Do you think the economy is contracting? Last month, of the 300 responses, 160 answered yes to the question. This month, 170 of the 290 responses indicated they felt the economy was contracting.At the .05 significance level, can we conclude that a larger proportion of the agents believe the economy is contracting this month?
Click here to see answer by reviewermath(514)

Question 630770: As part of a study of corporate employees, the director of human resources for PNC, Inc. wants to compare the distance traveled to work by employees at its office in downtown Cincinnati with the distance for those in downtown Pittsburgh. A sample of 35 Cincinnati employees showed they travel a mean of 370 miles per month. A sample of 40 Pittsburgh employees showed they travel a mean of 380 miles per month. The population standard deviation for the Cincinnati and Pittsburgh employees are 30 and 26 miles, respectively. At the .05 significance level, is there a difference in the mean number of miles traveled per month between Cincinnati and Pittsburgh employees?
(1)Is this a one-tailed or a two-tailed test?
(2)State the decision rule. (Negative amounts should be indicated by a minus sign. Round your answers to 2 decimal places.)
The decision rule is to reject H0:µC = µP if z is (Click to select)outside inside the interval (, )
Click here to see answer by richwmiller(9135)

Question 630772: According to the Census Bureau, 3.36 people reside in the typical American household. A sample of 27 households in Arizona retirement communities showed the mean number of residents per household was 2.70 residents. The standard deviation of this sample was 1.25 residents. At the .10 significance level, is it reasonable to conclude the mean number of residents in the retirement community household is less than 3.36 persons?
(a)
State the null hypothesis and the alternate hypothesis. (Round your answer to 2 decimal places.)

H0: μ ≥

H1: μ <

--------------------------------------------------------------------------------

(b)

State the decision rule for .10 significance level. (Negative amount should be indicated by a minus sign. Round your answer to 3 decimal places.)

Reject H0 if t <

(c)

Compute the value of the test statistic. (Negative amount should be indicated by a minus sign. Round your answer to 3 decimal places.)

Value of the test statistic

(d)

Is it reasonable to conclude the mean number of residents in the retirement community household is less than 3.36 persons?

(Click to select)Fail to rejectReject H0. Mean number of residents (Click to select)is necessarilyis not necessarily less than 3.36 persons.

Click here to see answer by richwmiller(9135)

Question 630774:
The American Water Works Association reports that the per capita water use in a single family home is 70 gallons per day. Legacy Ranch is a relatively new housing development consisting of 100 homes. The builders installed more efficient water fixtures, such as low flush toilets, and subsequently conducted a survey of the residences. Thirty-six homes responded, and the sample mean water use per day was 68 gallons with a standard deviation of 7.8 gallons per day.

At the .05 level of significance, is that enough evidence to conclude that residents of Legacy Ranch use less water on average?

(a)

What is the decision rule? (Negative amount should be indicated by a minus sign. Round your answer to 3 decimal places.)

Reject H0 : μ ≥ 70 and fail to reject H1 : μ < 70 when the test statistic is less than more than .

(b)

The value of the test statistic is . (Negative amount should be indicated by a minus sign. Round your answer to 2 decimal places.)

(c)

What is your decision regarding H0?

Click here to see answer by richwmiller(9135)

Question 630776: GfK Custom Research North America conducted identical surveys 5 years apart. One question asked of women was “Are most men basically kind, gentle, and thoughtful?” The earlier survey revealed that, of the 3,000 women surveyed, 2,010 said that they were. The later revealed 1,530 of the 3,000 women surveyed thought that men were kind, gentle, and thoughtful. At the .05 level, can we conclude that women think men are less kind, gentle, and thoughtful in the later survey compared with the earlier one?
(1)The pooled proportion is
(2)The decision rule is to reject if z
(3)The test statistic is z =
(4)What is your decision regarding ?
Click here to see answer by reviewermath(514)

Question 630948: Three friends board an airliner just before departure time. There are only 12 seats left, 4 of which are aisle seats. How many ways can the 3 people arrange themselves in available seats so that at least one of them sits on the aisle?
Click here to see answer by Edwin McCravy(8908)

Question 631043: one colored marker- red,blue,yellow, or green- is selected and a coin is tossed.
construct a tree diagram illustrating all the possible outcomes and list the sample space.
Click here to see answer by dfrazzetto(277)

Question 631089: Suppose E and F are independent events and P(E)= 1/3 and P(F)= 1/4. Find P intersection F. Find P(E U F).
Click here to see answer by stanbon(57307)

Question 631042: of 25 people shopping at Clothing Etc., 10 have bought a red cardigan sweater. Determine the empirical probability that the next shopper at Clothing Etc. will buy a red cardigan sweater.
Click here to see answer by stanbon(57307)

Question 631118: Suppose P(A)= 1/3, P(A or B)= 1/2, and P (A intersection B)= 1/10.
Find the P (A')
Find the P( B)
Find the P( B')
Click here to see answer by ewatrrr(10682)

Question 631129: If the are 13 job posiitons open, and all other things being equal, what is the probability the 13 men will be hired?
Click here to see answer by ewatrrr(10682)

Question 631147: jennifer is about to order dinner. She has the following choices. There are four main courses,six side dishes of which she gets a choice of two different sides and three desserts. How many possible meals are there?
Click here to see answer by ewatrrr(10682)

Question 631156: A population has a standard deviation σ of 27 units. (Give your answers correct to two decimal places.)
(a) Find the standard error for the mean if n = 10.
(b) Find the standard error for the mean if n = 42.
(c) Find the standard error for the mean if n = 76.

Click here to see answer by ewatrrr(10682)

Question 631157: A company ID card contains 7 digits, such as 92, 71, 042.
How many different ID numbers can be formed?
Click here to see answer by checkley79(3050)

Question 631155: Consider a normal population with μ = 36 and σ = 4.9. Calculate the z-score for an x of 47.6 from a sample of size 14. (Give your answer correct to two decimal places.)
Click here to see answer by ewatrrr(10682)

Question 631170: There are three bags. The first bag contains the letters: MATHEMATICS. The second bag contains the letters: ENGLISH. And the third bag contains the letters: SCIENCE. One letter is drawn from each bag one at a time starting with the first bag, then the second bag, then the third bag. What is the probability spelling the word ANN?
Click here to see answer by dfrazzetto(277)

Question 631171: There is a game that costs $5.00 to play. Two coins are tossed. You get $10.00 if two heads appear. You get $5.00 if one head appears. You get nothing if there are no heads. Is this game fair? Explain.
Click here to see answer by ewatrrr(10682)

Question 631173: We need to know how many fish are in a particular lagoon. We capture 72 fish, mark them, and then throw them back into the lagoon. The next day, 50 fish are captured and 13 were tagged from the day before. These fish are then thrown back into the lagoon. Estimate how many fish are in the lagoon.
Click here to see answer by stanbon(57307)

Question 631177: A class contains 25 boys and 2 girls, if 3 were chosen randomally.What is the probability of choosing 2 boys and 1 girl?
Click here to see answer by stanbon(57307)

Question 631177: A class contains 25 boys and 2 girls, if 3 were chosen randomally.What is the probability of choosing 2 boys and 1 girl?
Click here to see answer by ewatrrr(10682)

Question 631169: There is a 17% chance that two parents will pass a hereditary disease to any of their children. If they plan on having 4 children, what is the probability that at least one child will inherit the disease?
Click here to see answer by stanbon(57307)

Question 631166: Dr. Cawood's class is presented with a large bin that contains small plastic beads. The beads in the box are either purple or white. Dr. Cawood states that 25% of the beads are purple but Oliver, a student in Dr. Cawood's class believes that more than a quarter of the beads in the model box are purple.
Oliver takes a random sample of beads and finds that 19 out of the 52 beads sampled are purple. What is the p-value associated with the hypothesis test from Question 2?
Give your answer to 4 decimal places.
Click here to see answer by stanbon(57307)

Question 631111: Three of six people are going to be chosen for a committee. the positions on the committee will be chair, secretary, and treasure. In how many different ways can these positions be filled?
Click here to see answer by stanbon(57307)

Question 631182: Americans watch an average of 3.5 hours of television per person per day. If the standard deviation for the number of hours of television watched per day is 3.9 and a random sample of 266 Americans is selected, the mean of this sample belongs to a sampling distribution.
(a) What is the shape of this sampling distribution?
(1)skewed right normal
(2)symmetrical
(3)skewed left
(4)uniform

(b) What is the mean of this sampling distribution? (Give your answer correct to one decimal place.)

(c) What is the standard deviation of this sampling distribution? (Give your answer correct to two decimal places.)
Click here to see answer by jim_thompson5910(28593)

Question 631152: stated that Americans watch an average of 3.5 hours of television per person per day. If the standard deviation for the number of hours of television watched per day is 3.9 and a random sample of 266 Americans is selected, the mean of this sample belongs to a sampling distribution.
(a) What is the shape of this sampling distribution?
(1)skewed right normal
(2)symmetrical
(3)skewed left
(4)uniform

(b) What is the mean of this sampling distribution? (Give your answer correct to one decimal place.)

(c) What is the standard deviation of this sampling distribution? (Give your answer correct to two decimal places.)
Click here to see answer by ewatrrr(10682)

Question 631210: How do you write the binomial expansion for question # 1 & 2?
1. (2x+3)3 < - -3rd power
2. (2x-y)6 < - - 6th power
3. What is the 3rd term of the expansion for (x+3)7 < - - 7th power
4. What is the 5th term of the expansion for (2x-3y)5 < - - 5h power
5. find the coefficient of x3 < - - x to the 3rd power in the expansion (x+3)5 < - 5th power
Click here to see answer by stanbon(57307)

Question 631251: Of 1025 cars coming off the assembly line, 72 were found to be defective in some way
Click here to see answer by Alan3354(30993)

Question 631370: A beehive has a population of 200 bees.In one week,the population increases to 210.Predict the bee population in three weeks.
Click here to see answer by htmentor(789)

Question 631377: A hospital purchased 40 grams of a substance.Eight days later,when a doctor wanted to use some of the substance,he found that only 20 grams remained.Predict the amount remaining two weeks after the purchase of the substance.(Please show the solution.)
Click here to see answer by josmiceli(9671)

Question 631382: Please help me solve this Problems.
1. Numbered disks are placed in a box and one disk is selected at random.If there are 4 red disks numbered 1 trough 4, and 2 yellow disks numbered 5 thought 6, find the probability of selecting a disk numbered 3, given that a red disk is selected.

2. a card is dealt from a 52 card desk. What is the probability of not being dealt a queen of hearts?
3. find the measure of complement of the angle.
22 1/2 degrees.

Click here to see answer by ewatrrr(10682)

Question 631431: two dice are rolled: whats the probability of getting doubles or a sum of 4 or 10?
Click here to see answer by ewatrrr(10682)

Question 631456: Given a binomial distribution with n = 21 and p = 0.77, would the normal distribution provide a reasonable approximation? Why or why not?
Click here to see answer by jim_thompson5910(28593)

Question 631485: Construct a sample space of a couple who wants to have five children(excluding multiples)
Click here to see answer by jim_thompson5910(28593)

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