Tutors Answer Your Questions about Probabilityandstatistics (FREE)
Question 309911: Suppose your vehicle is licensed in a state that issues license plates that consist of three digits (between 0 and 9) followed by three letters (between A and Z). If a license number is selected randomly, what is the probability that yours is the one selected?
Click here to see answer by stanbon(69061) 
Question 309892: waiting times
single line: 6.5, 6.6, 6.7, 6.8, 7.1, 7.3, 7.4, 7.7, 7.7, 7.7
individual line: 4.2, 5.4, 5.8, 6.2, 6.7, 7.7, 7.7, 8.5, 9.3, 10.0
a)Find the mean, median, mode, variance, standard deviation, and range of each data set. Which appears to be the fastest?
b)Perform a hypothesis test to see if one method appears to be efficient than the other. (Hint: test 2 means). Show the null and alternative hypotheses, the critical value at 0.05, the test statistic, and the Pvalue. Lastly show (explain) your conclusion.
Click here to see answer by stanbon(69061) 
Question 310013: An important factor in selling a residential property is the number of people who look through the home. A sample of 15 homes recently sold in the Buffalo, New York, area revealed the mean number looking through each home was 24 and the standard deviation of the sample was 5 people. Develop a 98 percent confidence interval for the population mean.
Click here to see answer by stanbon(69061) 
Question 310140: a bookshelf contains six mysteries and three biographies. two books are selected at random without replacement.
a. what is the probability that both books are mysteries?
b. what is the probability that one book is a mystery and the otehr is a biography?
Click here to see answer by stanbon(69061) 
Question 310137: Evolutionary theories often emphasize that humans have adapted to their physical
environment. One such theory hypothesizes that people should spontaneously
follow a 24hour cycle of sleeping and waking—even if they are not exposed to
the usual pattern of sunlight. To test this notion, eight paid volunteers were
placed (individually) in a room in which there was no light from the outside and
no clocks or other indications of time. They could turn the lights on and off as
they wished. After a month in the room, each individual tended to develop a
steady cycle. Their cycles at the end of the study were as follows: 25, 27, 25, 23, 24, 25, 26, and 25.
Using the .05 level of significance, what should we conclude about the
theory that 24 hours is the natural cycle? (That is, does the average cycle length under these conditions differ significantly from 24 hours?) (a) Use the steps of hypothesis testing. (b) Sketch the distributions involved. (c) Explain your answer to someone who has never taken a course in statistics.
Click here to see answer by stanbon(69061) 
Question 310138: Twenty students randomly assigned to an experimental group receive an
instructional program; 30 in a control group do not. After 6 months, both groups
are tested on their knowledge. The experimental group has a mean of 38 on the
test (with an estimated population standard deviation of 3); the control group
has a mean of 35 (with an estimated population standard deviation of 5). Using
the .05 level, what should the experimenter conclude? (a) Use the steps of
hypothesis testing, (b) sketch the distributions involved, and (c) explain your
answer to someone who is familiar with the t test for a single sample but not
with the t test for independent means.
Click here to see answer by stanbon(69061) 
Question 310223: A group of files in a medical clinic classifies the patients by gender and by the type of diabetes ( 1 or 2). below is the number in each classification.
type 1 type 2
male 42 21
female 49 28
Find the probability that the selected individual is a female and type 2? Is the answer 1/5
Find the probability that the selected individual is a male and type 1? Is the answer 3/10
Find the probability that the individual gets type 1 knowing that the individual is a male?
Thank you,
Chrissie
Click here to see answer by stanbon(69061) 
Question 310228: When it is not raining, the probability of the Buchanan Bears winning a football game is 2/3. When it is raining the probability of the Bears winning is 3/15. The probability of rain on any day in December is 3/4.
What is the probability of the Bears winning on December 5?
Click here to see answer by stanbon(69061) 
Question 310197: Drawing a Card If one card is drawn from a deck, find the probability of getting these results:
a. An ace
b. A diamond
c. An ace of diamonds
d. A 4 or a 6
e. A 4 or a club
f. A 6 or a spade
g. A heart or a club
h. A red queen
i. A red card or a 7
j. A black card and a 10
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Question 310423: Bellevue Hospital in New York City uses 100.6 °F as the lowest temperature considered to indicate a fever.
a. (0.1 point) What percentage of normal and healthy adults would be considered to have
a fever? :
b. (0.1 point) Does this percentage suggest that a cutoff of 100.6 °F is appropriate?
Click here to see answer by stanbon(69061) 
Question 310526: Based on the information given for each of the following studies, decide
whether to reject the null hypothesis. For each, give (a) the Zscore cutoff (or
cutoffs) on the comparison distribution at which the null hypothesis should be
rejected, (b) the Z score on the comparison distribution for the sample score, and
(c) your conclusion. Assume that all populations are normally distributed
Click here to see answer by stanbon(69061) 
Question 310550: A restaurant offers the following choices for breakfast:
Eggs: scrambled, fried or poached
Meat: bacon, sausage, or ham
Toast: wheat, white, rye or pumpernickel
The Super Breakfast allows you to select two items for the meat list. How many breakfast combinations are possible if you select one each of the eggs and toast choices and two different meat choices?
Create sample space????????
Click here to see answer by stanbon(69061) 
Question 310547: A restaurant offers the following choices for breakfast:
Eggs: scrambled, fried, or poached
Meat: bacon, sausage, or ham
Toast: wheat, white, rye or pumpernickel
How many different breakfast combinations are possible if one item is selected from each list of eggs, meat, & toast choices?
I know I need to create the sample space but not sure how to get started.....
Click here to see answer by user_dude2008(1861) 
Question 310548: You have a bag of Skittles. The bag contains 50 Skittles. There are 5 colors, and 10 of each color. What is the probability of choosing the same color 3 times in a row? (You eat each Skittle.) Express your answer as a fraction in simplest form.
Click here to see answer by Fombitz(25151) 
Question 310543: You are trying to collect all nine baseball cards for an AllStar team. Each package of cards he can buy has one card of a member of the team. The cards are equally distributed among all the packages. How could you use a simulation to estimate the number of packages of cards you will need to buy to get all nine cards?
Click here to see answer by stanbon(69061) 
Question 310652: 2. A local tire store suspects that the mean life of a new discount tire is less that 39,000 miles. To check the claim, the store selects randomly 18 of these new discount tires. When they are tested, it is found that the mean life is 38,250 miles with a sample standard deviation s = 1200 miles. Assume the distribution is normally distributed.
a. Use the critical value t0 method from the normal distribution to test for the population mean . Test the company’s claim at the level of significance = 0.05.
(References: example 1 though 5 pages 397  401, end of section exercises 23 – 28 pages 404  405) (5 points)
1. H0 :
Ha :
2. =
3. Test statistics:
4. Pvalue or critical z0 or t0.
5. Rejection Region:
6. Decision:
7. Interpretation:
b. Use the critical value t0 method from the normal distribution to test for the population mean m. Test the company’s claim at the level of significance a = 0.01
(References: example 1 though 5 pages 397  401, end of section exercises 23 – 28 pages 404  405) (5 points)
1. H0 :
Ha :
2. a =
3. Test statistics:
4. Pvalue or critical z0 or t0.
5. Rejection Region:
6. Decision:
7. Interpretation:
Click here to see answer by stanbon(69061) 
Question 310647: 5. A researcher claims that the average age of people who buy lottery tickets is 65. A sample of 30 is selected and their ages are recorded as shown below. The standard deviation is 14. At α = 0.05 is there enough evidence to reject the researcher’s claim? Show all work.
49
63
80
52
22
80
72
56
70
56
24
46
70
74
70
61
65
71
39
74
79
76
71
49
62
68
71
67
69
45
Click here to see answer by Edwin McCravy(13211) 
Question 310792: From a large survey of customers using a chain of coffee shops, 60% of the customers are male, 50% purchase food, 15% are both Male and purchase food.
What are the probability that: A customer is both female and purchases food? A female customer purshases food? A customer purchasing food is female?
Click here to see answer by stanbon(69061) 
Question 310824: Hi, I really need help on my statistics final, the question is pretty long:
For my final I created a survey with the question: Is there a gender preference for fries or onion rings? My null and alternate hypotheses are:
HO: There is not a gender preference for either fries or onion rings.
HA: There is a gender preference for either fries or onion rings.
I've collected the data, and now I need to perform a hypothesis test and I just don't know which one to do. Do I do two seperate two proportion ztests? And if so, how would I represent that data?
I'm sorry for such a long question, and I would truly appreciate any help that you can give me.
Click here to see answer by stanbon(69061) 
Question 310836: 6. Given a level of confidence of 95% and a population standard deviation of 8, what other information is necessary:
(A) To find the Maximum Error of Estimate (E)?
(B) To find the sample size (n)?
(C) Given the above confidence level and population standard deviation, find the Maximum Error of Estimate (E) if n = 45. Show all your calculations. Show all work.
(D) For this same sample of n = 45, what is the width of the confidence interval around the population mean? Show all work.
(E) Given this same confidence level and standard deviation, find n if E = 2.5. (Always round to the nearest whole person.) Show all work.
Click here to see answer by stanbon(69061) 

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, 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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, 21241..21285, 21286..21330, 21331..21375, 21376..21420, 21421..21465, 21466..21510, 21511..21555, 21556..21600, 21601..21645, 21646..21690, 21691..21735, 21736..21780, 21781..21825, 21826..21870, 21871..21915, 21916..21960, 21961..22005, 22006..22050, 22051..22095, 22096..22140, 22141..22185, 22186..22230, 22231..22275, 22276..22320, 22321..22365, 22366..22410, 22411..22455, 22456..22500, 22501..22545, 22546..22590, 22591..22635, 22636..22680, 22681..22725, 22726..22770, 22771..22815, 22816..22860, 22861..22905, 22906..22950, 22951..22995, 22996..23040, 23041..23085, 23086..23130, 23131..23175, 23176..23220, 23221..23265, 23266..23310, 23311..23355, 23356..23400, 23401..23445, 23446..23490, 23491..23535, 23536..23580, 23581..23625, 23626..23670, 23671..23715, 23716..23760, 23761..23805, 23806..23850, 23851..23895, 23896..23940, 23941..23985, 23986..24030, 24031..24075, 24076..24120, 24121..24165, 24166..24210, 24211..24255, 24256..24300, 24301..24345, 24346..24390, 24391..24435, 24436..24480, 24481..24525, 24526..24570, 24571..24615, 24616..24660, 24661..24705, 24706..24750, 24751..24795, 24796..24840, 24841..24885, 24886..24930, 24931..24975, 24976..25020, 25021..25065, 25066..25110, 25111..25155, 25156..25200, 25201..25245, 25246..25290, 25291..25335, 25336..25380, 25381..25425, 25426..25470, 25471..25515, 25516..25560, 25561..25605, 25606..25650, 25651..25695, 25696..25740, 25741..25785, 25786..25830, 25831..25875, 25876..25920, 25921..25965, 25966..26010, 26011..26055, 26056..26100, 26101..26145, 26146..26190, 26191..26235, 26236..26280, 26281..26325, 26326..26370, 26371..26415, 26416..26460, 26461..26505, 26506..26550, 26551..26595, 26596..26640, 26641..26685, 26686..26730, 26731..26775, 26776..26820, 26821..26865, 26866..26910, 26911..26955, 26956..27000, 27001..27045, 27046..27090, 27091..27135, 27136..27180, 27181..27225, 27226..27270, 27271..27315, 27316..27360, 27361..27405, 27406..27450, 27451..27495, 27496..27540, 27541..27585, 27586..27630, 27631..27675, 27676..27720, 27721..27765, 27766..27810, 27811..27855, 27856..27900, 27901..27945, 27946..27990, 27991..28035, 28036..28080, 28081..28125, 28126..28170, 28171..28215, 28216..28260, 28261..28305, 28306..28350, 28351..28395, 28396..28440, 28441..28485, 28486..28530, 28531..28575, 28576..28620, 28621..28665, 28666..28710, 28711..28755, 28756..28800, 28801..28845, 28846..28890, 28891..28935, 28936..28980, 28981..29025, 29026..29070, 29071..29115, 29116..29160, 29161..29205, 29206..29250, 29251..29295, 29296..29340, 29341..29385, 29386..29430, 29431..29475, 29476..29520, 29521..29565, 29566..29610, 29611..29655, 29656..29700, 29701..29745, 29746..29790, 29791..29835, 29836..29880, 29881..29925
