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

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

Question 614879: A set of data is normally distributed with a mean of 500 and standard deviation of 100.
· What would be the standard score for a score of 433?
· What percentage of scores is between 500 and 433?
· What would be the percentile rank for a score of 433?

Click here to see answer by stanbon(57246)

Question 614918: 7 percent of tools manufactured by a factory are defective. What is the probability that in a shipment of 625 such tools (a) 8 percent or more, and (b) 7 percent or less will be defective?
Click here to see answer by stanbon(57246)

Question 614875: Please help me find the area under the standard normal curve:
I. to the right of z = -1.36
II. to the left of z = -1.36

Click here to see answer by stanbon(57246)

Question 579284: In the number 9765, what is the value of the digit 7
Click here to see answer by tipc(1)

Question 614960: Can I get a step-by-step explanation on how to work this problem out please? :(
A Math test has a mean of 41 and standard deviation of 12.0. Find the corresponding z scores for:

I. a test score of 35
II. a test score of 69
Click here to see answer by Theo(3458)

Question 614873: Please help me find the following:
P(z > 2.43)

Click here to see answer by Theo(3458)

Question 614980: The independent probability of a passenger arriving for a booked flight on a Maxi service is 0.8. The airline booked 225 passengers and there are 195 seats available on Maxi..Use the Normal distribution to find the probability for a given flight more booked passengers arrive than there are seats available.
Click here to see answer by stanbon(57246)

Question 615019: Please help me answer the following:
(A) Find the binomial probability P(x = 4), where n = 12 and p = 0.40.
(B) Set up, without solving, the binomial probability P(x is at most 4) using probability notation.
(C) How would you find the normal approximation to the binomial probability P(x = 4) in part A? Please show how you would calculate µ and σ in the formula for the normal approximation to the binomial, and show the final formula you would use without going through all the calculations.
Click here to see answer by stanbon(57246)

Question 615048: would the correlation between x and y in the table below be positive or negative find the missing value of y in the table. x 1 2 3 4 y 4 3 2 ?
how would the values of this table be interpreted in terms of linear regression
if a line of best fit is placed among these points plotted on a coordinate system would the slope be positive or negative
Click here to see answer by stanbon(57246)

Question 615061: A university admitted 100 students who transferred from other institutions. Of these students, 34 transferred from two-year community colleges, 25 transferred from private four-year institutions, and the rest transferred from public four-year institutions. If two different students are to be selected at random from the 100 students, what is the probability that both students selected will be students who transferred from two-year community colleges?
I want to know how to solve it , not only the answer for the question .
Thank you.
Click here to see answer by scott8148(6628)

Question 615052: I DEARLY NEED HELP WITH THIS PROBLEM..I HOPE SOMEBODY COULD HELP ME..TANX AND GOODBLESS
A large manufacturer has purchased an insurance policy for $500,000 per year to insure itself against 4 specific types of losses. The costs associated with each type of loss and their probabilities are listed in the accompanying table. The probability that no loss will occur is .63 and it is assumed that at most one type of loss will occur in a given year. Of the total cost of policy 20% is to cover administrative expenses.
Cost --- Probability
$ 100,000 -- .15
$ 800,000 -- .10
$ 1,500,000 -- .08
$ 2,500,000 -- .04
a) What is the expected profit to the insurance company on this policy?
b) What is the standard deviation of the profits to the insurance company?
Click here to see answer by stanbon(57246)

Question 615113: According to the US Small Business Administration, small businesses provide 75% of the net new jobs added to the economy. Consider a random sample of 1000 new jobs.
(a) Find the probability that the sample contains 800 new jobs provided by small businesses.
(b) What is the most likely number of new jobs to be provided by small businesses?
(c) Find and interpret the mean.
Click here to see answer by stanbon(57246)

Question 615011: Amedical researcher wishes to determine the percentage of females who take vitamins he wishes to be 99% confident that the estimate is within 2 percentage points of the true proportion a recent study of 180 females showed that 25% took vitamins. how large should the sample size be? if no estimate of the sample proportion is available how large should the sample be?
I do not know how to find what the sample size should be? so I am completely lost on this problem-I don't know where to start help!
Click here to see answer by stanbon(57246)

Question 615171: Can someone please help me. I have seen other answers but they do not match the ones I have to use. I do not undstand how to do these. Thanks! Consider the following scenario in answering questions 5 through 7.
Multiple myeloma or blood plasma cancer is characterized by increased blood vessel formulation in the bone marrow that is a prognostic factor in survival. One treatment approach used for multiple myeloma is stem cell transplantation with the patient’s own stem cells. The following data represent the bone marrow microvessel density for a sample of 7 patients who had a complete response to a stem cell transplant as measured by blood and urine tests. Two measurements were taken: the first immediately prior to the stem cell transplant, and the second at the time of the complete response. Use these data to answer questions 5 through 7.
Patient 1 2 3 4 5 6 7
Before 158 189 202 353 416 426 441
After 284 214 101 227 290 176 290
5. Perform an appropriate test of hypothesis to determine if there is evidence, at the .05 level of significance, to support the claim that the mean bone marrow microvessel density is higher before the stem cell transplant than after the stem cell transplant? What is the value of the sample test statistic?
A. z = 1.8424
B. t = 1.8424
C. t = 2.7234
D. p = 2.7234
6.What is the p-value associated with the test of hypothesis you conducted?
A. p = .057493
B. p = .114986
C. p = .942597
D. p = .885014
7. At the .01 level of significance, is there sufficient evidence to conclude that the mean bone marrow microvessel density is higher before the stem cell transplant than after the stem cell transplant?
A. No
B. Yes
C. Cannot Determine

Click here to see answer by stanbon(57246)

Question 615069: you are given the following data number of abscences 0,1,2,3,4,5 final grades 96,92,71,66,60,51 find the correlation coefficient for data find equation for the regression line for data and predict the final grade ofa student who misses 3.5 days
Click here to see answer by stanbon(57246)

Question 613986: Hello,
I have received the below assignment question, and im trying to go through my usual hypothesis steps (HATPC) however I cant seem to state the null and alternate hypothesis as they give no numbers in the research question ? I worked out the sample proportions and came up with the below but not sure if its correct, any help would be great thanks.
H0:P1 (Forum members) > p2 (non forum members)
H1:P1(Forum members) < or equal to p2 (non forum members)

Research Question: Do community forums on ecologically sustainable development
increase community awareness of the need for local council planning in regard to water resource management?
In order to raise community awareness, a local council held a series of community forums on ecologically sustainable development. At the end of these forums participants were encouraged to develop goals and actions for their local area, and were also asked to complete a questionnaire rating the following sustainability issues in order of importance with regard to local council planning:
 Agriculture
 Energy use
 Environmental protection
 Fisheries ecosystem management
 Land use planning
 Water resource management
The forums were held in a local council area which includes a section of the Cooks River.The Cooks River starts in Bankstown and flows 23 kilometres east and south east into Botany Bay. One part of the forum addressed the significant decline in water quality due to the extreme degradation of the Cooks River catchment area. Most of the natural vegetation in the catchment area has been cleared and the area has been subjected to large-scale dumping of industrial and domestic waste including sewage, and stormwater pollution. 120 randomly selected participants from the forums were selected. 42 of these participants had rated water resource management as the most important issue. A second random sample was selected from local residents who had not attended these community forums. Of these 150 residents, 35 rated water resource management as the most important issue. Carry out an appropriate hypothesis test to address the research question
Click here to see answer by surfpro128(1)

Question 615256: the sales of a business consist of 10 men and 10 women. they will choose 9 at random what the chance of choosing 5 men and 4 women
Click here to see answer by stanbon(57246)

Question 615243: x has normal distribution with a mean of 80.0 and a standard deviation of 3.5. Find the following:
A)P(x<75.0)
B) P(78.0 C) P(x>85.0)
Click here to see answer by stanbon(57246)

Question 615223: Draw eight cards from a standard deck of cards with replacement.
What is the probability that of these first eight cards that five are spades?
I come up with =====.001981?
Click here to see answer by stanbon(57246)

Question 615234: A manufacturing process has 100 customer orders to fill. Each order requires one component part that is purchased from a supplier. However, typically, 2% of the components are identified as defective, and the components can be assumed to be independent.
a. If the manufacturer stocks 100 components, what is the probability that the 100 orders can be filled without reordering components?
b. If the manufacturer stocks 102 components, what is the probability that the 100 orders can be filled without reordering components?
c. If the manufacturer stocks 105 components, what is the probability that the 100 orders can be filled without reordering components?
Click here to see answer by stanbon(57246)

Question 615310: if the correlation co efficient is 0.32 what is the sign of the slope regression line as the correlation co efficient decreases from 0.78 to 0.71 do the points of the scatter plot move toward the regression line or away from it
Click here to see answer by stanbon(57246)

Question 615228: I have problems figuring out 3 questions
1) Assume that a procedure yields a binomial distribution with a trial repeated n=5 times. Find the probability of x= 2 successes given that the probability p=0.75 of successes on a single trial.
2) Assume that adults have IQ scores that are normally distributed with a mean of 102 and a standard deviation of 12. Find the IQ score that separates the bottom 25% from the top 75%
3) Heights of adult men are normally distributed with a mean of 69 inches and standard deviation of 2.8 inches. If an adult man is randomly selected, what is the probability that he is taller than 73.2 inches
Click here to see answer by stanbon(57246)

Question 615360: hello, im having trouble with this problem :
-x/7+4≥3x
thank you
Click here to see answer by lwsshak3(6469)

Question 615451: Using hypothesis testing, I am trying to solve the following question: In a survey of 300 owners of cars equipped with seat belts, 165 stated that they regularly use this equipment. The remaining 135 reported only infrequent or no use of the seatbelts. The investigator wishe to know whether this data provides sufficient evidence to indicate that fewer than 60% of the sampled population regualrly uses safety belts. Let alpha= 0.01.
Click here to see answer by stanbon(57246)

Question 615407: Roll a pair of dice. What is the probability you roll a 12 given you have rolled higher than a 9?
Click here to see answer by stanbon(57246)

Question 615334: 25% staff make use of a program. If 20 are randomly selected, find probability that 6 will use program. Round to 4 decimal places
Click here to see answer by stanbon(57246)

Question 615452: A plastics company wishes to estimate the mean impact strength of a spool. How many spools should the company test if it wishes to have an interval width of 30 psi with 95% confidence? Previous experince indicates that an acceptable estimate of standard deviation squared is 4900.
Click here to see answer by stanbon(57246)

Question 615359: I have lost here with 2 different formula it's likely the same for me ,f(x) = n nCr x p^x(1 - p)^n-x or the Discrete population Probability D??which one is corrector and why?
Because not all airline passengers show up for their reserved seat, an airline sells 125 tickets for a flight that holds only 120 passengers. The probability that a passenger does not show up is 0.10, and the passengers behave independently.
a)What is the probability that every passenger who shows up can take the flight?
b)What is the probability that the flight departs with empty seats?
c)What is the probability that the flight departs with exactly 5 empty seats?
Thanks so much in advance!
Click here to see answer by stanbon(57246)

Question 615197: There a 100 ducks in a pond. 15 of them have red dots on them. If three ducks are randomly picked. What is the probability that 2 of them are ducks with a red dot? Once a duck is picked, it does not go back in the pond.
Here is what I tried.
15/100 X 14/99
Click here to see answer by stanbon(57246)

Question 615496: Determine whether each of the distributions given below represents a probability distribution. Justify your answer.

(a)
x 1 2 3 4
p(x) 3.8 1/2 7/24 1/3
(b)
x 3 6 8
p(x) 2/25 .1 4.5
(c)
x 20 35 40 50
p(x) 0.54 0.12 -0.03 0.37
Click here to see answer by jim_thompson5910(28504)

Question 615661: Hi, Can you tell me what the C means in some of your answers - I don't know how to calculate this..... e.g. 20C6*0.25^6*0.75^14 =0.1686 the answer you gave me to my previous question. Sue
Click here to see answer by jim_thompson5910(28504)

Question 615703: Hi, i really need help on this question
Goverment wants to give tax breaks to the 15% of population with the lowest salary, the mean salary is normally distributed with $42150 and std. dev of $4530
a. the cut-off margin of income to be eligible for the tax break?
b. the minimum income of 5% of the population with highest income.
c. the percentage of population with income between $30,000 and $70,000.
Click here to see answer by Theo(3458)

Question 615732: The employees at a General Motors assembly plant are polled as they leave work. Each is asked, “What brand of automobile are you riding home in?” The random variable to be reported is the number of each brand mentioned. Is x a binomial random variable? Justify your answer.
Click here to see answer by Theo(3458)

Question 615735: A student takes a multiple choice exam with 10 questions 6 possible selection per answer. What is the probability that the student gets at least one question right?
Click here to see answer by vksarvepalli(154)

Question 615839: 1.A person selects a card from a standard deck. If the card is red, she must pay $1. If it is a black card between 2 and 10, she wins 50 cents. If is a black picture card, she wins $2. If it is a black ace she wins $5. What is the expected value of her gain or loss from the game?
Click here to see answer by solver91311(16868)

Question 615853: Can someone please help I am still not understanding.
Suppose we want to determine the (binomial) probability (p) of getting 0 (zero) heads in 5 flips of a 2-sided coin. Using Table 2 in Appendix B of the text, what values of n, x, and p would we use to look up this probability, and what would be the probability?
I know that n= 5 and x= O p=0.05
The table

n x 0.01 0.05 0.10 0.20 0.30 0.40 0.50 0.60 0.70
5 0 .951 .774 .590 .328 .168 .078 .031 .010 .002

Click here to see answer by jim_thompson5910(28504)

Question 615851: 6.The scores for an admissions test have a mean of 1200 with a standard deviation of 60. A random sample of 64 scores is selected and the sample mean is calculated.
a)The sample mean is Normally distributed. What are the mean and the standard deviation for the distribution of the sample mean?
b)What is the probability that the sample mean will be larger than 1205?

Click here to see answer by stanbon(57246)

Question 615922: Answer the following:
- If the correlation coefficient is -0.53, what is the sign of the slope of the regression line?
- As the correlation coefficient increases from 0.51 to 0.56, do the points of the scatter plot move toward the regression line, or away from it?
Click here to see answer by jim_thompson5910(28504)

Question 616006: draw a ball from an basket with 3 blue balls, 5 orange balls and 7 green balls
What is the probability you draw a blue or green ball?
Click here to see answer by jim_thompson5910(28504)

Question 129230: A license plate is to consist of three digits followed by two uppercase letters. Determine the number of different license plates possible if repetition of numbers and letters is not permitted.
Click here to see answer by Cecilmx6(1)

Question 616110: There are 10 people at a party, five men and five women. If four people are selected at random, what is the probability that two men and two women are selected?
Click here to see answer by stanbon(57246)

Question 616071: A history teacher gives a 28 question T-F exam. In how many different ways can the test be answered if the possible answers are T or F, or possibly to leave the answer blank?
Click here to see answer by stanbon(57246)

Question 616146: Consider a population with µ=74.5 and σ=3.04.
(A) Calculate the z-score for x=75.7 (the x has a line over it) from a sample of size 18.
(B) Could this z-score be used in calculating probabilities using Table 3 in Appendix B of the text? Why or why not?
I got the answer for part (A) as (75.7 - 74.5) / [3.04 / sqrt (18)] = 1.674
I need help with part (B) please
TABLE 3 Cumulative Areas of the Standard Normal Distribution
The entries in this table are the cumulative probabilities for the standard normal distribution z (that is, the normal distribution with mean 0 and standard deviation 1). The shaded area under the curve of the standard normal distribution represents the cumulative probability to the left of a z-value in the left-hand tail.

Click here to see answer by ewatrrr(10682)

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