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

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 Question 234656: Al goes 8 mph; Ben goes 22 mph in the opposite direction. How many hours has Ben traveled when they are 180 miles apart? Click here to see answer by rfer(15570)

 Question 234955: When you toss a pair of dice, each containing the digits 1 through 6, what is the probability that the sum of the values face-up on the cubes will not be 3? a) 17/18 b) 1/6 c) 5/6 d) 18/36 e) 3/36. Click here to see answer by Theo(5548)

 Question 234951: What is regression co-efficient? How does it differ from a correlation co-efficient? Click here to see answer by stanbon(69061)

 Question 234924: it is assumed that labour productivity of particular members in a factory can be described by a normal distribution with sigma=3.what is probability that a sample mean calculated for 9 randomly chosen workers differs from the population mean by more than 2 units? Click here to see answer by stanbon(69061)

 Question 234913: From past experience, it is known 90% of one-year-old children can distinguish their mother's voice from the voice of a similar sounding female. A random sample of 60 one-year-olds is given this voice recognition test. Find the probability at most 56 of the children recognizes their mother's voice? Find the probability that at least 45 of the children recognize their mother’s voice? Find the probability that 50 to 58 (inclusive) children recognize their mother’s voice? what would the Binomial Table with probabilities for this problem look? Click here to see answer by stanbon(69061)

 Question 234981: Three coins are tossed in the air. what is the probability that exactly two of them turn up heads? Click here to see answer by stanbon(69061)

 Question 235056: five cards are dealt, what is the probability that the fifth one is a king Click here to see answer by solver91311(20879)

 Question 235136: The life span of one species of a maple tree is normally distributed with mean 20 years and standard deviation 2.3 years. If one tree is choosen at random, what is the probability it will live 21 years or longer? What is the probability that the average lifetime of 9 such trees will be 21 years or more? Click here to see answer by stanbon(69061)

 Question 235126: Ed earned 88 on his math midterm and 84 on his english midterm. In his math class the mean score was 75 with standard deviation 8. In his english class the mean score was 73 with standard deviation 5. Convert each score to a standard score, then find which was the higher score relative to the rest of the class. Click here to see answer by stanbon(69061)

 Question 235035: What is the probability that a 89% foul shooter will make at least 2 shots in a basketball game? I know it is some sort of conditional probability, but I have now idea on what formula I need to use to solve it and my book is not very helpful. Click here to see answer by stanbon(69061)

 Question 235267: A bag contains 16 yellow marbles, 6 green marbles, and 7 red marbles. What is the chance of drawing a yellow marble? If a yellow marble is drawn the first time and then a second marble is drawn without replacement, what is the probability of drawing a second yellow marble. Give solution in reduced fraction form, separated by a comma. Click here to see answer by stanbon(69061)

 Question 235276: A factory worker places 86 newly created circuits on a shelf to be checked for quality. Of these, 6 will not work correctly. Suppose that she is asked to randomly select two circuits, without replacement, from the shelf. What is the chance that both circuits she selects will be defective? Approximate the soulution to the nearest ten thousandth. Click here to see answer by stanbon(69061)

 Question 235235: How many different ways can a couple have 3 daughters and 2 sons in five distinct pregnancies (no multiple births). list all gender string (GGGBB etc) and compute the probability this happens. Click here to see answer by jim_thompson5910(33401)

 Question 235129: The pretzel pack company advertized that their pretzels weigh 2.5 ounces. The weights are normally distributed with mean 2.5 ounces and standard deviation 0.15 ounces. For a pretzel pack selected at random find the probabilty that it weighs less than 2.2 ounces and find the probability that it weighs more than 2.8 ounces. Click here to see answer by stanbon(69061)

 Question 235316: An oil drilling company knows that it costs \$25,000 to sink a test well. If oil is hit, the income for the drilling company will bve \$425,000. If only natural gas is hit, the income will be \$125,000. If nothing is hit, there will be no income. If the probability of hitting oil is 1/40 and the probability of hitting gas is 1/20, what is the expectation for the drilling company? Should the company sink the test well. Click here to see answer by stanbon(69061)

 Question 235379: the fm radio stations with high signal strength in new orleans breaks down into the following categories: hip hop 2 religious 6 country 2 rock 3 talk radio 2 other 5 if someone driving in new orleans tuned to a fm station at random, what would be the chance he would get a relirious or talk radio station? give in fraction at lowest terms. Click here to see answer by checkley77(12844)

 Question 235547: Tthe mean amount purchased by each customer at a casino is 23.50 euros. The population is positively skewed and the standard deviation is not known. A MARKETING REseARCHER TOOK A sample of 50 customers. If the standard deviation of the sample is 5 euros, what is the likelihood that the sample mean is greater than 22.5 but less then 25 euros Click here to see answer by stanbon(69061)

 Question 235550: The apollo space craft program lasted from 1967 to 1972 and incl 13 missions. The missions lasted from as little as 7 hrs to as long as 301 hrs. The duration of each flight is listed below: 9-195-241-301-216-260-7-244-192-147-10-295-142- Is this dataset a sample or a population? find the mmean and median of the flight time? Find the range and quartile range of the flight times. Click here to see answer by stanbon(69061)

 Question 235577: a miniature golf course offers a free game to golfers who make a hole-in-one on the last hole.Last week, 56 out of 270 golfers made a hole-in-one on the last hole.Find the experimental probability that a golfer makes a hole-in-one on the last hole.please round your answer to two decmial places. Click here to see answer by stanbon(69061)

 Question 235546: a manufacture of tv tubes has for many years used a process giving a mean tube life of 4900 hrs and a standard deviation of 1200 hours. A new process is tried to see if it will increase the life significantly. A sample of 100 new tubes gave a mean life of 5000 hrs. Is the new process better than the old process at 1% level of significant? Construct hypotheses test it and interpret the result. Click here to see answer by stanbon(69061)

 Question 235541: A car battery manufacturer introduces a new technique to increase the life of the battery. 25 batteries were tested and got a mean life of 4.6 years with a standard deviation of 0.70 years. Construct a 90% confidence interval for the mean life of the new battery. THX Click here to see answer by stanbon(69061)

 Question 235513: i have a question in the grouped data in statistics , they asking the probability that an emloyee . taken at random , earns more than 20000 pounds , total workers are 68 and they have group which interval is between 15000-24.999 . plzzzzzz help meeeeee Click here to see answer by stanbon(69061)

 Question 235411: I submitted this question on yesterday and did not get a response. I would like to thank the tutor for helping me on this problem. A telephone survey gives 670 consumers two choices: Do they prefer Coke or Pepsi? Exactly 158 of those surveyed state that they prefer Coke. Assuming that = 0.10, test the hypothesis that the proportion of the population that prefers Coke is 50%. · State the null and alternate hypotheses · Calculate the sample proportion · Calculate the value of the test statistic. · Determine the critical value(s). · State your decision: Should the null hypothesis be rejected? Click here to see answer by stanbon(69061)

 Question 235413: Two groups of ten sprinters run 100 meters. The times required by sprinters in the first group are as follows: 12.0 12.9 10.1 14.6 11.9 11.3 13.0 12.9 13.3 10.0 The times required by sprinters in the second group are as follows: 11.6 12.5 12.3 10.2 16.3 17.0 19.1 18.7 12.3 16.4 Assuming that = 0.02, test the hypothesis that the means of the two populations are equal. · State the null and alternate hypotheses · Calculate the mean and standard deviation for each group · Calculate the value of the test statistic. · Determine the critical value(s). · State your decision: Should the null hypothesis be rejected? Thank you so very much for helping with this problem. I really do appreciate all of your hard work. Click here to see answer by stanbon(69061)

 Question 235843: Solve the following system of equations by Gauss-Elimination method x + y + z = 9 x – 2y + 3z = 8 2x + y – z = 3 Click here to see answer by Stitch(468)

 Question 235847: In a college 30% students fail in Physics, 25% fail in Mathematics and 10% students fail in both. One student is chosen at random. What is the probability that a) He fails in Mathematics if he has failed in Physics b) He fails in Physics if he has failed in Mathematics. c) He fails in Physics or Mathematics. Click here to see answer by stanbon(69061)

 Question 235846: From a bag containing 2 rupee-coins and 3 twenty paise coins, a person is asked to draw two coins at random. Find the values of his expectatioon. Click here to see answer by stanbon(69061)

 Question 235828: There is a 50% chance of rain on Saturday and a 50% chance of rain on Sunday. What is the probability of 2 sunny days this weekend? Click here to see answer by stanbon(69061)

 Question 235409: I need your help in working this problem out. Thank you very much... A watch manufacturer creates watch springs whose properties must be consistent. In particular, the standard deviation in their weights must be no greater than 2.0 grams. Fifteen watch springs are selected from the production line and measured; their weights are 1, 4, 8, 7, 1, 5, 1, 4, 1, 4, 3, 9, 1, 3, and 2 grams. Assume = 0.01. · State the null and alternate hypotheses · Calculate the sample standard deviation · Determine which test statistic is appropriate (chi-square or F), and calculate its value. · Determine the critical value(s). · State your decision: Should the null hypothesis be rejected? Click here to see answer by stanbon(69061)

 Question 235408: The US Mint selects ten pennies from the production line to test the hypothesis that the mean weight of each penny is at least 6 grams. The normally-distributed weights (in grams) of these pennies are as follows: 6, 6, 8, 5, 9, 5, 9, 2, 3, 8. Assume = 0.01. · State the null and alternate hypotheses · Calculate the sample mean and standard deviation · Determine which test statistic is appropriate (z or t), and calculate its value. · Determine the critical value(s). · State your decision: Should the null hypothesis be rejected? I submitted this question on yesterday and did not get a response. I would like to thank you tutor for all of your hard work. Click here to see answer by stanbon(69061)

 Question 235907: Let two cards be dealt successively, without replacement, from a standard 52-card deck. Find the probability of each event: a)no face cards b)club second, given diamond first Click here to see answer by josmiceli(13716)

 Question 235921: Suppose that a researcher is interested in estimating the mean systolic blood pressure,u, of executives of major corporations. He plans to use the blood pressures of a random sample of executives of major corporations to estimate u. Assuming that the standard deviation of the population of systolic blood pressures of executives of major corporations is 25 mm Hg, what is the minimum sample size needed for the researcher to be 90% confident that his estimate is within 5 mm Hg of u? Click here to see answer by stanbon(69061)

 Question 235920: A decade-old study found that the proportion of high school seniors who felt that "getting rich" was an important personal goal was 66%. Suppose that we have reason to believe that this proportion has changed, and we wish to carry out a hypothesis test to see if our belief can be supported. State the null hypothesis Ho and the alternative hypothesis H1 that we would use for this test. Click here to see answer by stanbon(69061)

 Question 235922: In how many ways can a doubles game of tennis be arranged from five boys and eleven girls if each side must have one boy and one girl? Click here to see answer by solver91311(20879)

 Question 235378: A factory worker places 86 newly created circuits on a shelf to be checked for quality. of these 6 will not work correctly. Suppose that she is asked to randomly select 2 circuits, without replacement. what is the chance that both circuits she selects will be defective? approximate to the nearest ten thousandth. Click here to see answer by stanbon(69061)

 Question 235963: I have answered some of these but am not for sure if they are correct, the others, I am not for sure. Thanks in advance 1. Decide whether the random variable is discrete or continuous. a.The number of bottles of water drunk in Florida in August 2008 Discrete b.The number of wasps in the lab test nest Discrete c.The height of sophomores in a required US History class at Ridgemont High in 2008 Continuous d.The number of players on the Washington Redskins Discrete e.The speed of cars starting in the Darlington 500 in 2008 Continuous 2. Decide whether the distribution is a probability distribution. If it is not a probability distribution, identify the property that is not satisfied. x P(x) 1 0.200 2 0.238 3 0.245 4 0.307 No it is not a probability distribution. It does not equal 1. 0.200 + 0.238 + 0.245 + 0.307 = 0.99 Section 4.2: Binomial Probability 4. In a local college, 60% of the math majors are women. Fifteen math majors are chosen at random. (1 points each) a. What is the probability that exactly 6 are women? b. What is the probability that 5 or less women are selected? c. What is the probability that 10 women are selected? d. Find the mean  e. Find the variance 2 5. A multiple choice test has 20 questions with each having 4 possible answers with one correct. Assume a student randomly guesses the answer to every question. (2.5 points each) a. What is the probability of getting exactly 11 correct answers? b. What is the probability of getting less than 9 correct answers? Click here to see answer by stanbon(69061)

 Question 236031: Can you PLEASE help me with this homework problem?? I appreciate any help you can give! Table I White Black Hispanic Asian Foreign Total Dept. 1. 4 0 1 1 2 8 Dept. 2. 2 4 1 1 0 8 Dept. 3. 1 2 3 1 1 8 Dept. 4. 4 0 1 1 2 8 Dept. 5. 3 2 1 0 2 8 Total. 14 8 7 4 7 40 Table II Female Male Total Black 6 2 8 White 6 8 14 Hispanic 3 4 7 Asian 2 2 4 Foreign 5 2 7 Total 22 18 40 From Table 1: What is the probabilty of choosing a White employee from Dept. 2 and then a Hispanic employee from Dept. 3? What is the probability of choosing a Foreigner or an Hispanic both from Department 5? From Table 2: What is the probability of choosing a Black male or a Foreign male? Click here to see answer by stanbon(69061)

 Question 236051: Contruct a binominal distribution using n=6 and p=0.36 X P(x) o 1 2 3 4 5 6 Click here to see answer by stanbon(69061)

 Question 235071: Find the area under the standard normal curve between z = -1.53 and z = 0. Round the answer to 4 decimal places. Click here to see answer by stanbon(69061)