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

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 Algebra: Probability and statistics Solvers Lessons Answers archive Quiz In Depth

 Question 464998: How many ways are there to select a committee to develop a discrete mathematics course at a university if the committee is to consist of four faculty members from the mathematics department and three from the computer science department, if there are 10 faculty members of the mathematics department and 12 of the computer science department? Click here to see answer by edjones(7569)

 Question 465006: K. Historically, the campus police write a ticket on 15% of the vehicles they stop on campus; violations include speeding, no valid sticker, illegal parking, etc. Student leaders will take a survey of 400 students who had been stopped by the campus police. What is the probability that 55 or more of these students have been issued a ticket? Note: Be sure to identify any assumptions or conditions needed Click here to see answer by stanbon(57347)
 Question 465006: K. Historically, the campus police write a ticket on 15% of the vehicles they stop on campus; violations include speeding, no valid sticker, illegal parking, etc. Student leaders will take a survey of 400 students who had been stopped by the campus police. What is the probability that 55 or more of these students have been issued a ticket? Note: Be sure to identify any assumptions or conditions needed Click here to see answer by edjones(7569)

 Question 465000: Why can we not draw causal conclusions based on correlations among variables? In other words, explain why the phrase, “Correlation does not imply causation” is true. Identify an example from real life (i.e., work, politics, family life) where there is an apparent relationship between two behaviors and discuss the possible explanations for that relationship. Click here to see answer by stanbon(57347)

 Question 464970: A certain brand of cookie is sold in a package containing six cookies. Sometimes the cookies are broken. Present the probability distribution for the number of broken (defective) cookies in a package when the defective rate is 30%. Describe the shape of the histogram. Determine each of the following: mean, median, mode, range, and standard deviation. Find the probability that the number of broken cookies in the package is more than 2. Click here to see answer by edjones(7569)

 Question 465078: 80% of the voters favor Ms. Stein if 4 voters are chose at random, find the probability that noe support Ms Stein and the probability that at leaast one support Ms Stein Click here to see answer by robertb(4012)

 Question 465156: assuming that the mean systolic blood pressure of a normal adult is 120 millimeters of mercury(mmHg)and the standard deviation is 5.6. assume the variable is normally distributed, i). if an individual is selected, find the probability the individual's pressure will be between 120 and 121.8 mmHg ii). if a sample of 30 adults is randomly selected, find the probability that the sample mean will be between will be between 120 and 121.8 mmHg Click here to see answer by edjones(7569)

 Question 465155: in a certain hospital, maternity, it has been observed that the probability of getting a baby boy is 0.32. if 10 expectant ladies are observed, find the probability that, i) exactly three of them are males ii)at least 9 are females iii) none is a boy Click here to see answer by edjones(7569)

 Question 465161: How many ways are there to select a committee to develop a discrete mathematics course at a university if the committee is to consist of four faculty members from the mathematics department and three from the computer science department, if there are 10 faculty members of the mathematics department and 12 of the computer science department? Click here to see answer by edjones(7569)

 Question 465167: the frequency distribution of scores on an examination is closely described by a bell shaped frequency curve and the distribution has a mean of 57.5 and a standard deviation of 10. i) what percentage of candidates would be awarded grade A if the cut-off for grade A is 75 Marks? Click here to see answer by stanbon(57347)

 Question 465186: Suppose that the reliability of a test for hepitisus is specified as follows. Of the people with hepatitis 96% have a positive reaction and 4% have a negative reacti0on, of the people free of hepititis, 95% have a negative reaction and 5% have a positive reation. From a large population of witch 0.05% of the people have hepititis , A PERSON IS SELECTED AT RANDOM AND IS GIVEN THE TEST IS POSITIVE, WHAT IS THE PROBABILITY THAT THE PERSON ACTUALLY HAS HEPITITIS? Click here to see answer by stanbon(57347)

 Question 465190: Joe feels the probability of getting an A in history is .3, the probability of getting a A in physcology is 0.4, and the probability of getting an A in history or Physcology is 0.6 . What is the probability of getting an A IN BOTH SUBJECTS? Click here to see answer by stanbon(57347)

 Question 465193: Withoust consultation , each of four organizations announced a one-daY convention to be held during june. Find the probability that at least two organizations specify the same day for their convention? Click here to see answer by stanbon(57347)

 Question 465198: three horses calle A,B,C are all racing aginst each other the probability that A will win is 1/7 the probability that B will win is 1/3. What is the probability that c will win?? Also what is the odds that C will win 11 to___? Click here to see answer by stanbon(57347)

 Question 465244: Hello, I do not understand this question at all. I do not really understand Statistics at all honestly. If you could help me I would greatly appreciate it! :) Thank you! Why can we not draw causal conclusions based on correlations among variables? In other words, explain why the phrase, “Correlation does not imply causation” is true. Identify an example from real life (i.e., work, politics, family life) where there is an apparent relationship between two behaviors and discuss the possible explanations for that relationship. Click here to see answer by stanbon(57347)

 Question 465267: victoria goes to the deli for sandwiches and orders 5 roast beefs and 4 ham sandwiches. They are wrapped and put into a paper bag. What is the probability that two sandiches choosen at random will be a roast beef ? What is the probability that the two sandwiches will be alike?? Click here to see answer by ewatrrr(10682)

 Question 465265: a nusery school teacher collected a picture from each of the 8 children in the class. She wants to hang the pictures in two rows of four. how many diffrent arrangements are possible? Click here to see answer by solver91311(16885)

 Question 464210: A college requires applicants to have an ACT score in the top 12% of all test scores. The ACT scores are normally distributed, with a mean of 21.5 and a standard deviation of 4.7. i) type of distribution: _sampling distributions of mean______________ ii) find the mean: __21.5 points________ and standard deviation: ____4.7 points______ iii) find the following: a. Find the lowest test score that a student could get and still meet the college’s requirement. b. If 1300 students are randomly selected, how many would be expected to have a test score that would meet the college’s requirement? c. How does the answer to part (a) change if the college decided to accept the top 15% of all test scores? Click here to see answer by stanbon(57347)

 Question 464211: The weight of potato chips in a medium size bag is stated to be 8 ounces. The amount that the packaging machine puts in these bags is believed to be normally distributed with a mean of 8.2 ounces and standard deviation of 0.12 ounces. i) type of distribution: __sample distributions of sample_____________ ii) find the mean of the population: _8.2 ounces______ and standard deviation of the population: ___.12 ounces______ iii) find the probability of a bag sold that is underweight. 4.78%__________ iv) Some of the chips are sold in “bargain packs” of 3 bags. Find the mean of the distribution of mean of all bargain packs: 8.2 ounces_______ and standard deviation: _.0693 ounces________ v) What’s the probability that the mean of the 3 is underweight? ___normalcdf(-1E99, 8, 8.2, .0693)= .001951?________ vi) What’s the probability that the mean weight of 24-bag case of potato chips is below 8 ounces? __________ Click here to see answer by stanbon(57347)

 Question 465346: An urn contains 8 balls identical in every way except color. There are 4 blue balls, 3 red balls, and 1 yellow ball. a) You draw 2 balls from the urn but replace the first before drawing the second. What is the probability that both balls are red? b) You draw 2 balls from the urn but do not replace the first before drawing the second. What is the probability that both balls are red? c) Explain the difference (if any) in the two problems. Click here to see answer by ewatrrr(10682)

 Question 465361: normal distribution has a mean of meu= 22 with sigma= 3. What score is needed to place in the top 14% of the distribution? Click here to see answer by stanbon(57347)

 Question 465315: 1. Suppose you decide to bet on red on each of 10 consecutive spins of the roulette wheel. Suppose you lose all five of the first wagers, which means that on the first five spins of the wheel, red has not come up once. Which of the following is true? A. The wheel is not working properly. It favors outcomes that are not red. Hence, during the next five spins of the wheel, we’re likely to continue to see few red outcomes. B. What happened on the first five spins tells us nothing about what will happen on the next five spins. C. We’re due for a win, so the sixth spin of the wheel is very likely to come up red. D. You should get more spins of red on the next five spins of the wheel because we didn’t get any on the first five spins. Click here to see answer by stanbon(57347)

 Question 465364: Find the t values that form the boundaries of the critical region for a two-tailed test with a α = 0.5 for each of the following df values. a) df = 8 b) df = 15 c) df = 24 Click here to see answer by stanbon(57347)

 Question 465264: a licenes plate contains six letters and digits with no repetions allowed. How many diffrent licenes plates are possible? Click here to see answer by stanbon(57347)

 Question 465368: given a regular 52- card deck, what is the probabliuty of getting a 5-card hand with at least one heart? and what is the probabilty of getting a 5-card hand that consists of 3 red cards and 2 black cards? Click here to see answer by stanbon(57347)

 Question 465433: A psychologist wants to interview subjects with IQ scores in the top 1%. IQ scores are normally distributed with mean of 100 and a standard deviation of 15. Find the score that separating the top 1% of IQ from the bottom 99%. Click here to see answer by stanbon(57347)

 Question 465432: The Ivy College Technology Center reports that 80% of the incoming freshmen purchase a printer from the Center, 35% buy a laptop from the Center, and that 60% of those who buy a laptop from the Center also buy a printer there. What is the probability that a randomly selected freshman student a) purchased a laptop computer and a printer from the Center? b) purchased a laptop computer or a printer from the Center? c) purchased a laptop at the Center, given that (s)he purchased a printer there? Click here to see answer by jorel1380(2518)

 Question 465430: Suppose A and B are events with P(A) = 1/4, P(B) = 2/5, and P(A or B) = 1/2. a) Are the events A and B mutually exclusive? Explain your reasoning. b) What is P(A and B)? c) Are the events A and B independent? Explain your reasoning. Click here to see answer by robertb(4012)
 Question 465430: Suppose A and B are events with P(A) = 1/4, P(B) = 2/5, and P(A or B) = 1/2. a) Are the events A and B mutually exclusive? Explain your reasoning. b) What is P(A and B)? c) Are the events A and B independent? Explain your reasoning. Click here to see answer by stanbon(57347)

 Question 465454: Find the value of E, the margin of error, for c = 0.90, n = 2.8 and s = 64 Click here to see answer by stanbon(57347)

 Question 465376: what is the probability of rolling a 5 given that an odd number turns up? and an even number given that a number less than 5 turns up? Click here to see answer by stanbon(57347)

 Question 465331: Suppose A and B are events with P(A) = 1/4, P(B) = 2/5, and P(A or B) = 1/2. a) Are the events A and B mutually exclusive? Explain your reasoning. b) What is P(A and B)? c) Are the events A and B independent? Explain your reasoning. Click here to see answer by stanbon(57347)

 Question 465499: I'm stuck on this :/ some one please help SAT verbal scores are normally distributed with a mean of 430 and a standard deviation of 120 If 1 of the student is randomly selected, find the probability that he or she obtained a score higher than 440. Click here to see answer by edjones(7569)

 Question 465475: SAT verbal scores are normally distributed with a mean of 430 and a standard deviation of 120 If 1 of the student is randomly selected, find the probability that he or she obtained a score higher than 440. Click here to see answer by edjones(7569)

 Question 465510: A study found that the average life expectancy is 53 years with a standard deviation of 7.5 years. If a person is selected at random, what is the probability that the person will die before the age of 65? A. 94.52% B. 82.89% C. 94.95% D. 88.49% Click here to see answer by edjones(7569)

 Question 465440: According to the Sleep Foundation, the average night's sleep is 6.8 hours (Fortune, March 20, 2006). Assume the standard deviation is .7 hours and that the probability distribution is normal. What is the probability that a randomly selected person sleeps more than 8 hours (to 4 decimals)? What is the probability that a randomly selected person sleeps 6 hours or less (to 4 decimals)? Doctors suggest getting between 7 and 9 hours of sleep each night. What percentage of the population gets this much sleep (to the nearest whole number)? % Click here to see answer by edjones(7569)

 Question 465515: A sample of 400 racing cars showed that 80 cars cost over \$700,000. What is the 99% confidence interval of the true proportion of cars costing over \$700,000? Click here to see answer by edjones(7569)

 Question 465597: 22. A fair die is rolled three times. A random variable X denotes the number of occurrences of 6’s. What is the probability that X will have the value which is not equal to 0. Click here to see answer by stanbon(57347)

 Question 465550: the nursing club at a large college in nairobi believes that the group consists of 10% first years, 20% second years, 40% third years and 30% fourth years. the membership for the club this year consisted of 14 first years, 19 second years, 51 third years and 16 fourth years. at ᾰ=10% test the advisers conjecture Click here to see answer by stanbon(57347)

 Question 465602: 25.If the variance of a random variable X is given Var(X)=3. Then Var(2X) is 30.The lifetime of a machine part has a continuous distribution on the interval (0, 40) with probability density function . Calculate the probability that the lifetime of the machine part is less than 6. 31.The lifetime of a machine part has a continuous distribution on the interval (0, 40) with probability density function . Calculate the probability that the lifetime of the machine part is less than 5. 32.If Var(X)=2, find Var(-3X+4). Click here to see answer by stanbon(57347)

 Question 465601: Problem 9.52 At Ajax Spring Water, a half-liter bottle of soft drink is supposed to contain a mean of 520 ml. The filling process follows a normal distribution with a known process standard deviation of 4 ml. A) Which sampling distribution would you use if random supplies of 10 bottles are to be weighed? B) Set up hypotheses and a two-tailed decision rule for the correct mean using the 5% level of significance. C) If sample of 16 bottles shows a mean fill of 515ml, does this contradict the hypothesis that the true mean is 520ml? Click here to see answer by stanbon(57347)

 Question 465545: Why the Z test is usually inappropriate for small sample size? Click here to see answer by stanbon(57347)