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

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

Question 141594: An auditor reviewed 25 oral surgery insurance claims from a particular surgical office, determining that the mean out-of-pocket patient biling above the reimbursed amount was $275.66 with a standard deviation of $78.11. (a) At the 5 percent level of significance, does this sample prove a violation of the guideline that the average patient should pay no more than $250 out-of-pocket? State your hypothesis and decision rule. (b) Is this a close decision?
Click here to see answer by stanbon(57290)

Question 141565: one letter of the alphabet appears on each of 26 cards. you choose a card at random and then replace it. then you choose a secind card. assume Y is consonant. P(I,A)
Click here to see answer by stanbon(57290)

Question 141514: The management of White Industries is considering a new method of assembling its golf cart. The present method requires 42.3 minutes, on the average, to assemble a cart. The mean assembly time for a random sample of 24 carts, using the new method, was 40.6 minutes, and the standard deviation of the sample was 2.7 minutes. Using a 0.10 level of significance, setup a Hypothesis test. Can we conclude that the assembly time using the new method is faster?
Click here to see answer by stanbon(57290)

Question 141448: The probability is 1 in 4,000,000 that a single auto trip in the United States will result in a fatality. Over a lifetime, an average U.S. driver takes 50,000 trips. (a) What is the probability of a fatal accident over a lifetime? Explain your reasoning carefully. Hint: Assume independent events. Why might the assumption of independence be violated? (b) Why might a driver be tempted not to use a seat belt “just on this trip”?

Click here to see answer by stanbon(57290)

Question 141752: This problem is driving me nuts!! Please Assist :/
"Two cards are drawn from a standard deck of 52 cards. Find each Probability
P(Both Kings or Both Black)
P(Both Face Cards of Both Red)

Click here to see answer by stanbon(57290)

Question 141846: Does lovastatin (a cholesterol-lowering drug) reduce the risk of heart attack? In a Texas study,
researchers gave lovastatin to 2,325 people and an inactive substitute to 2,081 people (average age
58). After 5 years, 57 of the lovastatin group had suffered a heart attack, compared with 97 for the
inactive pill. (a) State the appropriate hypotheses. (b) Obtain a test statistic and p-value. Interpret
the results at α = .01. (c) Is normality assured? (d) Is the difference large enough to be important?
(e) What else would medical researchers need to know before prescribing this drug widely? (Data
are from Science News 153 [May 30, 1998], p. 343.)

Click here to see answer by stanbon(57290)

Question 141845: An experimental medication is administered to 16 people who suffer from migraines. After an
hour, 10 say they feel better. Is the medication effective (i.e., is the percent who feel better greater
than 50 percent)? Use α = .10, explain fully, and show all steps.

Click here to see answer by stanbon(57290)

Question 141844: 9.65 A consumer agency tested 290 hams, finding that 64 were underweight. (a) Construct a 95 percent
confidence interval for the true percent of underweight hams. (b) If the goal is to reduce the incidence
of underweight hams to 25 percent or less, does this sample show that the goal is being
achieved? (c) Explain how this confidence interval is equivalent to a two-tailed test at α = .05.
(Data are from Detroit Free Press, March 9, 1999, p. 2A.)

Click here to see answer by stanbon(57290)

Question 141843: 9.63 In the Big Ten (the NCAA sports league) a sample showed that only 267 out of 584 freshmen football
players graduated within 6 years. (a) At α = .05 does this sample contradict the claim that at
least half graduate within 6 years? State your hypotheses and decision rule. (b) Calculate the
p-value and interpret it. (c) Do you think the difference is important, as opposed to significant?

Click here to see answer by stanbon(57290)

Question 141967: A sample of 25 concession stand purchases at the October 22 matinee of Bride of Chucky showed
a mean purchase of $5.29 with a standard deviation of $3.02. For the October 26 evening showing
of the same movie, for a sample of 25 purchases the mean was $5.12 with a standard deviation of
$2.14. The means appear to be very close, but not the variances. At α = .05, is there a difference
in variances? Show all steps clearly, including an illustration of the decision rule. (Data are from
a project by statistics students Kim Dyer, Amy Pease, and Lyndsey Smith.)

Click here to see answer by stanbon(57290)

Question 141966: 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(57290)

Question 141965: 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.

DATA
Accident Rate for Dallas Fire Trucks
Statistic Red Fire Trucks Yellow Fire Trucks
Number of accidents x1 = 20 accidents x2 = 4 accidents
Number of fire runs n1 = 153,348 runs n2 = 135,035 runs

Click here to see answer by stanbon(57290)

Question 141842: A coin was flipped 60 times and came up heads 38 times. (a) At the .10 level of significance, is the
coin biased toward heads? Show your decision rule and calculations. (b) Calculate a p-value and
interpret it.

Click here to see answer by stanbon(57290)

Question 141841: On eight Friday quizzes, Bob received scores of 80, 85, 95, 92, 89, 84, 90, 92. He tells Prof.
Hardtack that he is really a 90+ performer but this sample just happened to fall below his true
performance level. (a) State an appropriate pair of hypotheses. (b) State the formula for the test
statistic and show your decision rule using the 1 percent level of significance. (c) Carry out the
test. Show your work. (d) What assumptions are required? (e) Use Excel to find the p-value and
interpret it.

Click here to see answer by stanbon(57290)

Question 142044: A fair coins is tossed 5 times.
What is the probability of obtaining exactly 3 heads?
I found a formula that looks like C(5,3)=5!/[3!(5-3)!]
My problem is, I don't know if this formula is right, or how to solve it. I believe this is supposed to tell you the number of possible outcomes???
Click here to see answer by stanbon(57290)

Question 142078: Please help this problem is giving me a headache.

What is the probability of choosing a man and is wearing a hat. There are 20 men with hats, 30 men without hats, 25 woman with hats, and 10 woman without hats.
Click here to see answer by stanbon(57290)

Question 142058: This is the socond problem I am struggling with. Any help would be appericated. thank you.
7.55 Tire pressure in a certain car is a normally distributed random variable with mean 30 psi (pounds per square inch) and standard deviation 2 psi. The manufacturer’s recommended correct inflation range is 28 psi to 32 psi. A motorist’s tire is inspected at random. (a) What is the probability that the tire’s inflation is within the recommended range? (b) What is the probability that the tire is under-inflated? *(c) The Alliance of Automotive Manufacturers has developed a microchip that will warn when a tire is 25 percent below the recommended mean, to warn of dangerously low tire pressure. How often would such an alarm be triggered? (See The Wall Street Journal, July 14, 2004.)
Click here to see answer by stanbon(57290)

Question 142057: I need help understanding this problem. I am lost
In the Ardmore Hotel, 20 percent of the customers pay by American Express credit card. (a) Of the next 10 customers, what is the probability that none pay by American Express? (b) At least two? (c) Fewer than three? (d) What is the expected number who pay by American Express? (e) Find the Standard deviation.
Any help would be great. Thank you
Click here to see answer by stanbon(57290)

Question 142201: Please help me.
What is the probability of rolling a 4 or a 9 on fair dice?
Click here to see answer by Edwin McCravy(8901)

Question 142200: Please help with this problem.
What is the probability of not yellow for a standard package of 8 crayons?
Click here to see answer by stanbon(57290)

Question 142199: Please help with this problem.
What is the probility that a family has 5 sons only?
Click here to see answer by stanbon(57290)

Question 142198: Please help with this problem.
What is the probability of choosing a man that is wearing a hat. There are 20 men with hats, 30 men without hats, 25 women with hats, and 10 women without hats.
Click here to see answer by stanbon(57290)

Question 142256: Please help with this problem.
You are given 12 to 1 odd against hitting a solid 17 on Roulette number. This means that you win $12 if you succeed and you lose $1 if you fail. Calculate the expected value for one roll.
Click here to see answer by stanbon(57290)

Question 142307: sonia cds are all mixed up in a box twelve cds are rock eight are jazz and five are classical if she reaches in and selects three at random find the probability.
p (all jazz)
Click here to see answer by stanbon(57290)

Question 130205: Convert each of the following x intervals to standardized z intervals:
a) 5 ≤ x ≤ 8
b) x ≥ 4
Convert each of the following z intervals to raw score x intervals:
c) z ≥ -2
d) 0 ≤ z ≤ 2
e) z ≤ 3
Click here to see answer by stanbon(57290)

Question 127278: In an election, it was estimated that person A would receive 200 of the 300 electoral votes. What was the standard error? This question is due on day 6.
Click here to see answer by stanbon(57290)

Question 142493: Hi please can you tell me if the probability value of 0.0133 is significant or not?

Click here to see answer by stanbon(57290)

Question 142504: A bag only has blue and green chips. The probability of drawing a blue chip is 5/12. Find P(green).

Thanks agian!!!!
Click here to see answer by solver91311(16877)

Question 142503: A ranch has 132 cows. You pick 32 of them at random and find that 18 of those cows have spots. Predict the numbe of cows on the ranch that have spots.

Thanks so much!!!!!
Click here to see answer by solver91311(16877)

Question 142508: Suppose you roll a number cube twice. What is the pobability of getting a 2 on the first roll and a 5 on the second roll?

Thanks yall agian.
Click here to see answer by rapaljer(4667)

Question 142502: Pam and Tony play a game 18 times. Tony wins 8 times and Pam wins 10 times.

A.) Find the experimental probability that Pam wins.
B.) Find the expeimental probability that Tony wins.
C.) If Pama and Tony play the game 18 more times, must the experimental pobabilites remain the same? Explain please

Thank you 1000 million times!!!!
Click here to see answer by solver91311(16877)

Question 142507: Determine if the events ae independent. Explain you answers.
A.) You roll two number cubes. One shows a 3 Th other shows a 1.

B.) You draw a ed marble fom hte bag containg red and yellow marbles. You do no put the marble back. you draw another red marble.
Click here to see answer by rapaljer(4667)

Question 142506: A bag contains four red,four blue, and thee green cubes. Cubes are drawn twice with replacement. Find each probability.

1.) P(both red)

Thank yall
Click here to see answer by rapaljer(4667)

Question 142501: Suppose you read in the newspaper that the probability of rain is 10%. Write this probability as a fraction and as a decimal.

Thanks so much
Click here to see answer by rapaljer(4667)

Question 142505: Use the counting principle to find the number of permutaions of the letters in GLACIER.

Thank yall
Click here to see answer by rapaljer(4667)

Question 142426: describe the combined variation that is modeled by each formula.
V=lwh
Click here to see answer by stanbon(57290)

Question 142549: Exercise using Excel

The School Committee members of a midsized New England city agreed that a strict
discipline code has caused an increase in the number of student suspensions. The
number of suspensions for September 1992 - February 1993 for a sample of the schools is provided below. {Data}
The average number of suspensions for the previous year mean{X bar} = 130.5 and the Standard deviation {STDEV}
was 158.2
(a) Set up the null and alternative hypothesis to test if the averave number of suspensions
has changed.
(b) Test your hypothesis with alpha = 0.05.
(c) Find the p value.
(d) Display the data in an Excel Chart to see if it is reasonable to assume that the underlaying population
distribution is normal.
(e) Based on the p value, what can you conclude about the average number of suspensions?

Data:
Suspensions
Central 245 a) - c) mu = 195
MCDI 1 Step 1 H(0) mean equal 130.5
Chestnut 65 H(A) mean not equal 130.5
Duggan 133 Sigma is given as = 158.2
Kennedy 97 Step 2 Critical Values (Z) = +/-1.96 because alpha is 0.05
Forest Park 149 (n)^0.5 Z P(Z<-1.352) p = 2*P(Z<-1.352) = 2*0.0885
Putnam 1024 Step 3 Test Statistic Z 3.317 Calculate Z here in cell H25.
Kiley 56 p value = 0.177
Central Academy 254 Why is Z minus?
Commerce 114 Step 4/5 d) See Below.
Bridge 7 e) What do you think?
STDEV= 287.15
mu = 195.00

ReOrder
MCDI 1
Bridge 7
Kiley 56
Chestnut 65
Kennedy 97
Commerce 114
Duggan 133
Forest Park 149
Central 245
Central Academy 254
Putnam 1024

Click here to see answer by stanbon(57290)

Question 142565: Find a confidence interval for μ assuming that each sample is from a normal population.
a. ¯x = 14, σ = 4, n = 5, 90 percent confidence
b. ¯x = 37, σ = 5, n = 15, 99 percent confidence
c. ¯x = 121, σ = 15, n = 25, 95 percent confidence
Click here to see answer by stanbon(57290)

Question 142566: Calculate the test statistic and p-value for each sample.
a. H0: μ = 60 versus H1: μ = 60, α = .025, ¯x = 63, σ = 8, n = 16
b. H0: μ ≥ 60 versus H1: μ < 60, α = .05, ¯x = 58, σ = 5, n = 25
c. H0: μ ≤ 60 versus H1: μ > 60, α = .05, ¯x = 65, σ = 8, n = 36
Click here to see answer by stanbon(57290)

Question 142794: Suppose three coins are tossed find each probability. Please do all
1.)P( exactly 1 tail)
2.)P(exactly 2 heads)
3.)P(3 tails)
4.)P(all the same)
5.)P(1 or more tails)
6.)P(3 heads)

Please help me thanks!!!
P.S Please do all

Click here to see answer by stanbon(57290)

Question 142835: Calculate the probability of drawing four cards out of a standard deck.
P(4 of a kind)
P(All the same suit)
P(All the same #)
Thanks So much!
Click here to see answer by stanbon(57290)

Question 142908: The probability of making a 6-ft putt is 60%. How many times should you expect to make it if you putt the flowing numbers?

1.) 5times
2.) 10 times
3.) 30 times
4.) 160 times

Thanks so much
Click here to see answer by vleith(2825)

Question 142909: Explain how using a spinner would help find the expeimental probability that a soccer player will score a goal on a penatly kick. Suppose the player makes 75% of his penatly kicks.

thanks!!!
Click here to see answer by vleith(2825)

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