Tutors Answer Your Questions about Probability-and-statistics (FREE)
Question 321023: The ages (in years) of seven people and the number of days they spent recovering in the hospital after surgery are given in the following table.
Age, x 12 21 38 44 59 63 70
Days in Hospital, y 4 6 7 5 9 11 12
Calculate the correlation coefficient, r.
Click here to see answer by Fombitz(13828)   |
Question 320859: I have several questions of the following nature. Need instructions of how they got this answer...this ones answer is "B"
A lab technician is tested for her consistency by taking multiple measurements of cholesterol levels from the same blood sample. The target accuracy a standard deviation of 1.3 or less. If 20 measurements are taken and their standard deviation is 1.9, is there enough evidence to reject the claim that her standard deviation is within the limit at α = .01?
A) No, comparing the test value 27.77 and the critical value 6.02.
B) Yes, comparing the test value 6.37 and the critical value 6.02.
C) No, comparing the test value 27.77 and the critical value 6.13.
D) Yes, comparing the test value 6.37 and the critical value 6.13.
Click here to see answer by stanbon(57246) |
Question 321051: Thickness measurments of ancient prehistoric Native American pot shards discovered in a Hopi Village were approximately normally distributed with a mean of 5.1mm and standard deviation of 0.9 mm. For 500 randomly selected shards, about how many would you expect to be between 3.2mm and 6.8mm thick? Find P 30,(the 30 is on the right side of the P but smaller) for the shard thickness?
Click here to see answer by stanbon(57246) |
Question 321048: The college Student senate is sponsoring a spring break Carribbean cruise raffle. The proceeds are to be donated to then samaritan Center for the homeless. A local travel agency donated the cruise, valued at $2,000. The students sold 2852 raffle tickets at $5 per ticket. Kevin bought six tickets. What is kevins expected value for the raffle? How much did kevin effectivly contribute to the samaritan center for the homeless?
Click here to see answer by stanbon(57246) |
Question 321174: in a random sample of 350 voters,200 are Republicans. If three voters are selected at random from this sample. what is the probability that
at least one of the voters is republican
all three of the voters are republican
none of the voters are republican
Click here to see answer by stanbon(57246) |
Question 321172: Can anyone please help with this question? :(
students can be categorized by gender (male or female), class (freshmen, sophomores, juniors, or seniors), and hair color (blonde, brunette, or redhead). Using any method, how many different categories would there be? Explain how you found your answer.
Click here to see answer by stanbon(57246) |
Question 321107: "A random sample of 80 cell phones was inspected in a cell phone factory. It was found that 6 of the cell phone is defective in some way. Based on this data, the auditor wants to perform a statistical test to see that the defective rate of cell phone produced by the factory is greater than 5%."
Click here to see answer by stanbon(57246) |
Question 321191: stan..if you can help me out once more i would appreciate so much :)
a combination lock has digits from 0 to 39. three numbers are required to open.
how many combinations are possible if you cannot repeat any digits?
how many combination are possible if you cannot have the same digit twice in a row?
this is what i came up with..59,280 for first one and can't figure out second one:(
Click here to see answer by Alan3354(30983)  |
Question 321193: The ages (in years) of seven people and the number of days they spent recovering in the hospital after surgery are given in the following table.
Age, x 12 21 38 44 59 63 70
Days in Hospital, y 4 6 7 5 9 11 12
Make a conclusion about the type of correlation.
Click here to see answer by stanbon(57246) |
Question 321195: The ages (in years) of seven people and the number of days they spent recovering in the hospital after surgery are given in the following table.
Age, x 12 21 38 44 59 63 70
Days in Hospital, y 4 6 7 5 9 11 12
Using the regression line, predict the value of y for x = 30.
Click here to see answer by stanbon(57246) |
Question 321228: The fracture strength of a certain type of manufactured glass is normally distributed with a mean of 581 MPa with a standard deviation of 13 MPa.
What is the probability that a randomly chosen sample of glass will break at, (Round your answers to 4 decimal places.)
(a) less than 581 MPa?
(b) more than 592 Mpa?
(c) less than 602 MPa?
Click here to see answer by stanbon(57246) |
Question 321248: JJ wants to study the eating habits of baby elephants. If she notices that they eat on average 4.3 lbs of grass each hour. What is the probability that the new elephant will eat more than 8 lbs of grass one hour?
Completely stuck on this probability and statistics problem, can someone please help me understand how to work this problem?
Click here to see answer by galactus(183)  |
Question 321280: You draw two cards from a standard deck of 52 cards and replace the first one before drawing the second. Find the probability of drawing a 4 for the first card and a 9 for the second card. Round your answer to the nearest thousandth.
Click here to see answer by stanbon(57246) |
Question 321278: The ages (in years) of seven people and the number of days they spent recovering in the hospital after surgery are given in the following table.
Age, x 12 21 38 44 59 63 70
Days in Hospital, y 4 6 7 5 9 11 12
Calculate the correlation coefficient, r.
Click here to see answer by stanbon(57246) |
Question 321277: The mean price of milk per gallon in the United States is $4.45 with a standard deviation of $0.35. Random samples of milk of size 40 are selected at grocery stores around the United States.
Use the Central Limit Theorem to find the mean and the standard error of the mean of the sampling distribution.
Click here to see answer by stanbon(57246) |
Question 321276: The mean price of computers at an electronics store is $850, with a standard deviation of $90. A random sample of 21 televisions is drawn from this population. What is the probability that the mean price of the sample is less than $830?
Click here to see answer by stanbon(57246) |
Question 321275: The ages (in years) of seven people and the number of days they spent recovering in the hospital after surgery are given in the following table.
Age, x 12 21 38 44 59 63 70
Days in Hospital, y 4 6 7 5 9 11 12
Make a conclusion about the type of correlation.
Click here to see answer by stanbon(57246) |
Question 321324: tom likes to lie in bed in the morning. the probability that he is late for school is 0.1. What is the possibility that he is late on monday, tuesday & wednesday. What is possibility that he is late on monday & tuesday but on time on wednsday. What is possibility that he is late on only one of the three mornings?
Click here to see answer by stanbon(57246) |
Question 321369: A point is chosen at random from within a circular region. what is the probability that the point is closer to the center of the region than it is to the boundary of the region.
A 1/4 B 1/3 C 1/2 D 2/3 E 3/4
Click here to see answer by galactus(183) |
Question 321387: Suppose four digits are to be randomly selected with repetitions allowed. The set of digits is {0, 1, 2, 3, 4, 5, 6, 7, 8, 9}. What is the probability that the four selected digits contain only even numbers?
Click here to see answer by stanbon(57246) |
Question 321495: There are two cookie jars on the shelf in the kitchen. The red one has 10 chocolate chip cookies and
15 gingersnaps. The blue jar has 20 chocolate-chip cookies and 10 gingersnaps. James goes down in the
middle of the night and without turning on the light chooses a jar at random. If the cookie is chocolate chip,
what is the probability that he got the cookie from the blue jar?
Click here to see answer by scott8148(6628)  |
Question 321545: 66% of students as a university live on campus. A random sample found that 20 of 40 male students and 40 of 50 of female students lived on campus. At the .05 level of significance, is there sufficient evidence to conclude that a difference exists between the proportion of male students who live on campus and the proportion of female students who live on campus?
what are the steps to figure this problem and what formula(s) should be used.
Click here to see answer by stanbon(57246) |
Question 321534: In comparing the two variances below, what is the test value and what are the degree of freedom that should be used?
Sample 1
Variance is 6
Number of values is 18
Sample 2
Variance is 11
Number of values is 29
Did I figure this right? Test Value = Sample 2 Variance / Sample 1 Variance = 11 / 6 = 1.83 and the degrees of freedom using the formula (n-1) is 18 - 1 = 17 and 29 - 1 = 28
Click here to see answer by stanbon(57246) |
Question 321770: please help! i've done several simpler ones on my own but i am stuck on this one. A carnival worker is tempting to play his game. He has a secret box which contains twenty $1 bill, ten $5 bills, and five $10 bills. you can draw one bill out per game; however, the cost of the game is $5. fill in the table for the profit you might win
Gain, x
Probability, P(x)
i can't figure out how to draw the distribution table on here but there are three colums and two rows:(
Click here to see answer by stanbon(57246) |
Question 321835: An urn contains 4 green, 6 blue and 10 yellow chips.
You pay $5 to draw a chip from the urn. Here are the rules of the game:
if you draw a green chip, the dealer returns you your bet and gives you an additional $5.
if you draw a blue chip, the dealer returns you your bet and gives you $1.
if you draw a yellow chip, the dealer keeps your $5.
What is the expected value of this game?
Tip: make a table with x-column money to win/lose (+/-) and probability column P(x)
that this happens, then calculate Expected Value of x E(x) for this distribution
Click here to see answer by Theo(3458)  |
Question 321835: An urn contains 4 green, 6 blue and 10 yellow chips.
You pay $5 to draw a chip from the urn. Here are the rules of the game:
if you draw a green chip, the dealer returns you your bet and gives you an additional $5.
if you draw a blue chip, the dealer returns you your bet and gives you $1.
if you draw a yellow chip, the dealer keeps your $5.
What is the expected value of this game?
Tip: make a table with x-column money to win/lose (+/-) and probability column P(x)
that this happens, then calculate Expected Value of x E(x) for this distribution
Click here to see answer by stanbon(57246) |
Question 321833: please help! been trying to make headway but am yet again at a loss..the local fire department plans to sell 500 raffle tickets for 2.00 each. first prize is 100. second prize is 50. and third prize is 25
fill in table
gain x ______________ ___________ _____________ _____________
prob px ______________ ____________ ____________ _____________
what is expected value?
how much money would the fire dept. have left after paying out the prizes with this fund raiser?
Click here to see answer by stanbon(57246) |
Question 321795: one last question for today if anyone can please help
construct a probability distribution for the following data
number of times students were tardy to class the first quarter
x, #of tardies 0 1 2 3 4
# of students 80 20 22 18 10
p(x)
i'm just confused on what to multiply what by to get the px..do you multiply by number of days in quarter or what....anything u can do to help is greatly appreciated!
Click here to see answer by stanbon(57246) |
Question 321910: Please help..I am not understanding this..I am taking an online course and I am lost with this
5. Find the probabilities.
a.From National Weather Service records, the annual snowfall in the TopKick Mountains has a mean of 92 inches and a standard deviation of 12 inches. If the snowfall from 36 randomly selected years are chosen, what it the probability that the snowfall would be less than 95 inches?
b.The loan officer rates applicants for credit. Ratings are normally distributed. The mean is 240 and the standard deviation is 60. If 49 applicants are randomly chosen, what is the probability that they will have a rating between 230 and 260? Round z scores to two decimal places.
Click here to see answer by stanbon(57246) |
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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, 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