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

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 Question 334829: On a standard measure of hearing ability, the mean is 300 and the standard deviation is 20. Give the Z scores for persons who score (a) 340, (b) 310, and (c) 260. Give the raw scores for persons whose Z scores on this test are (d) 2.4, (e) 1.5, (f) 0, and (g) . Click here to see answer by stanbon(60771)

 Question 334810: What is the difference between the null and alternative hypotheses statements in one-tailed and two-tailed tests? How do ethics affect your chosen level of significance Can anyone eplainthis to me...I am totally lost.???? Click here to see answer by stanbon(60771)

 Question 334646: A toy manufacturer wants to see how long, on average, a new toy captures 12 children's attention. He tests children selected at random and finds that their mean attention span is 7 minutes with a standard deviation of minutes. If we assume that attention spans are normally distributed at 29 minutes, find a 90% confidence interval for the mean attention span of children playing with this new toy. Click here to see answer by stanbon(60771)

 Question 335057: If 2 dice are rolled what is the probability that the score on the dice is 9 or they both show the same number? Click here to see answer by stanbon(60771)
 Question 335057: If 2 dice are rolled what is the probability that the score on the dice is 9 or they both show the same number? Click here to see answer by Edwin McCravy(9717)

 Question 335227: Please help me solve the following problem: The values of annual precipitation in Collage Station, texas from 1910 to 1979 are given. Find the following: 1. Probability that annual precipitation R in any year will be <38 inches? 2. Probability that annual precipitation R in any year will be >47 inches? 3. Probability of having two successive years with R<38 inches? 4. Probability of having a precipitation R between 36 Thanks!!! Click here to see answer by Fombitz(13828)

 Question 335182: Hello I need help with my statistic homework I can't understand how this formula works its random sample. the problem is a random sample of 600 high school boys showed 40 had taken diet pills during the past 30 days to lose weight the proportion of all high school boys who taken the diet pills to lose weight H0 p=0.10 Ha;p#0.10 1. state the null hypotheseis (H0) and the alternative hypothesesis (Ha) 2. verify necessary data conditions for a z statistic and calculate the z statistic 3. assuming the null hypothesis is true finf the p value ? 4.are the results statistically significant at a significance level of a=0.05 ?what is the conclusion to the context? Click here to see answer by jrfrunner(365)

 Question 335253: For a chi-square random variable with 12 degrees of freedom and a significance level of .025, the value of the chi-square critical value is 23.337. Which of the following computed values for the test statistic will lead to acceptance of the null hypothesis? a) 42.22 b) 28.43 c) 31.34 d) 26.34 e) 18.26 Click here to see answer by jrfrunner(365)

 Question 335263: For a chi-square random variable with 12 degrees of freedom and a significance level of 0.025 the value of the chi-square critical value is 23.337. Which of the following computed values of the test statistic will lead to acceptance of the null hypothesis? 1. 42.22 2. 28.43 3. 31.34 4. 26.34 5. 18.26 Click here to see answer by jrfrunner(365)

 Question 335258: Given the least squares regression line y^ = -2.88 + 1.77x, and a coefficient of determination of 0.81, the coefficient of correlation is? Click here to see answer by jrfrunner(365)

 Question 335273: The ages of 25 employees in a company are listed below in a stem and leaf plot. What is the probability that a worker chosen at random will have an age greater than or equal to 30 and less than or equal to 39? 2 0 2 6 7 9 3 0 3 4 5 6 8 8 9 9 4 2 4 5 6 7 5 2 3 4 7 6 1 3 Click here to see answer by Fombitz(13828)

 Question 335234: Could you explain the probability of selecting two people at random both having an IQ of 110 or above the mean is 100 and the deviation is 15 Click here to see answer by jrfrunner(365)

 Question 335287: Your statistics tutor wants you to determine a confidence interval estimate for the mean score in next exam. In the past the scores have been distributed normally with a mean of 74.2 and a standard deviation of 30.9. A 95% confidence interval if your class has 30 students is 1. (68.72;79.68) 2. (13.64;34.76) 3. (64.92;83.48) 4. (63.14;85.26) 5. (62.66;85.73) Click here to see answer by Fombitz(13828)

 Question 335318: Choose the correct answer: In statistics, linear regression refers to: a) Any relationship between two random variables b) Any approach to modelling the relationship between one or more variables denoted Y and one or more variables denoted X, such that the model depends linearly on the unknown parameters to be estimated from data c) Developing a regression model to be used for forecasting d) A contingency table using X and Y in the rows and columns e) Any statistical method that is used to provide the basic concepts for a student who is being trained to be a statistician Click here to see answer by solver91311(18785)

 Question 335471: The proportion of individuals insured by the All-Driver Automobile Insurance Company who received at least one traffic ticket during a five-year period is .15. Show the sampling distribution of –p if a random sample of 150 insured individuals is use to estimate the proportion having received at least one ticket. What is the probability that the sample proportion will be within +or- .03 of the population proportion? Click here to see answer by stanbon(60771)

 Question 335444: A person must score in the upper 2% of the population on an IQ test to qualify for membership in Mensa. If IQ scores are normally ldistributed with a mean of 100 and a standard deviation of 15, what score must a person have to qualify for Mensa? Click here to see answer by Fombitz(13828)

 Question 335506: annie has a box of colored pencils in her room. It contains 25 blue, 7 black, 10 yellow, 15 green, 2 purple, 18 red, 10 orange and 3 brown. What is the probability that she draws a green pencil replace it then draw red pencils? Click here to see answer by Fombitz(13828)

 Question 335520: The ages of 25 employees in a company are listed below: Use the stem & leaf plot to determine the shape of the distribution. Choose the best answer Click here to see answer by Fombitz(13828)

 Question 335382: An airline company found that 80% of their flights arrive to their destination on time. We are interested in selecting a sample of 5 flights and calculating the probability of all of them getting to their destination on time. Choose the best answer of the following Click here to see answer by Fombitz(13828)

 Question 335567: The usual life of a computer terminal at a university computer center is known to be normally distributed with a mean of 3.25 years and a standard deviation of .5 years. A. What proportion of computer terminals will have a useful life of at least 3 years? B. Historically, 20% of the terminals have had a useful life less than the manufacture's advertised life. What is the manufacture's advertised life for the computer terminals? Click here to see answer by stanbon(60771)

 Question 335693: a person takes a multiple choice test consisting of 6 questions with 4 choies for each question. what is the probability that the person will only get questions 2,3, and 5 correct? Click here to see answer by stanbon(60771)

 Question 335676: My Algebra I book has this question. I know how to solve it, but I want to understand WHY the formula works for finding probability. Here's the problem: "When you play a game with number cubes, you can find probabilities by squaring a binomial. Let A represent rolling 1 or 2 and B represent rolling 2,3,4, or 6. The probability of A is 1/3 and the probability of B is 2/3. Find the solution: (1/3A + 2/3B)squared." Again, I want to understand WHY the formula (1/3A + 2/3B)squared works for identifying probability. Thank you!! Click here to see answer by stanbon(60771)

 Question 335712: If there are a total of 5 doors, then how many ways can a student enter the hall by one door and exit by any door? Click here to see answer by Fombitz(13828)

 Question 335724: How many 2-letter code words can be formed from the first 6 letters of the alphabet if letters can be repeated? Click here to see answer by Fombitz(13828)

 Question 335715: There is seven types of jelly. They package gift boxes containing four jars of jelly, no two of which are of the same type. To reflect the three national chains through which the jelly is distributed, the producer uses three types of boxes. How many different gift boxes are possible? Click here to see answer by jrfrunner(365)

 Question 335737: You are a part of a group of 15 people. One person is selected at random. What is the percent probability that you will be chosen first? Click here to see answer by stanbon(60771)

 Question 335718: A corporation plans to fill 2 different posi- tions, V1 and V2. The office in Austin has 14 senior workers, while the one in Dallas has 15 senior workers. In how many ways can the 2 positions be filled if position V1 is filled from the Austin office but position V2 is filled from the Dallas office? Click here to see answer by stanbon(60771)

 Question 335763: It was reported that a certain population had a mean of 27. To test this claim, you selected a random sample of size 100. The computed sample mean and sample standard deviation were 25 and 7, respectively. At the 0.05 level of significance, you can claim that the average of this population is: Click here to see answer by stanbon(60771)

 Question 335773: It was reported that a certain population had a mean of 27. To test this claim, you selected a random sample of size 100. The computed sample mean and sample standard deviation were 25 and 7, respectively. At the 0.05 level of significance, you can claim that the average of this population is: a. not equal to 25. b. equal to 25. c. not equal to 27. d. equal to 27. Click here to see answer by stanbon(60771)

 Question 335781: 3. Your High School basketball team’s starting 5 players are listed at the following heights: 5’8” (68 inches) 5’10” (70 inches) 6’1” (73 inches) 6’2” (74 inches) 7’4” (88 inches) What is the median height on this team? What is the mean height? If you wanted to lull the opponent into a false sense of security, which statistic would you publish? Why? If you wanted to intimidate your opponent, which statistic would you publish? Why? Click here to see answer by rfer(13569)

 Question 335782: 1. Decide if the situation presented below contains a potential for bias. If it does, tell what the form of bias is, and how it can be prevented: A respected News organization has been taking polls prior to each Presidential Election by calling people on their home phones and asking who they plan to vote for. Over the years, they have been very accurate in their predictions. However, in 2008, somebody noticed that many people did not own home phones, and rather used cell phones full time. Cell phones are not listed in the directory assistance from which the News organization pulls its sample. Click here to see answer by jim_thompson5910(29613)

 Question 335779: After a sample of numbers is taken from a population, the 95% confidence interval is calculated out at {10.5, 12.0} What is the correct way to interpret this confidence interval? Choose one. A) 95% of all values in the population are between 10.5 and 12.0 B) The true population mean has to be between 10.5 and 12.0 C) There is a 95% probability that the true population parameter is between 10.5 and 12.0. D) The mean is between 10.5 and 12.0, and the standard deviation is 95. Click here to see answer by jrfrunner(365)

 Question 335824: The correct combination of a lock is first turn right to d1, then turn left to d2, and last turns to d3, where d1, d2, and d3 are selected from 0, 1, 2, ..., 50. How many different lock combinations are possible with such a lock, if a) the numbers may be repeated? b) the numbers may not be repeated? Click here to see answer by Theo(3556)

 Question 335835: HISTORY TEST RESULTS Score 100 95 90 85 80 75 70 65 60 Number of 1 2 4 1 3 2 2 0 1 Students The scores on Tuesday’s history test for 16 students are shown in the table above. Sam, who was the only student absent on Tuesday, will take the test next week. If Sam receives a score of 95 on the test, what will be the median score for the test? (A) 90 (B) 87.5 (C) 85 (D) 82.5 (E) 80 Click here to see answer by stanbon(60771)

 Question 335831: The unemployment rate in a city is 12%. Find the probability that at most 2 out of 10 people from this city sampled at random are unemployed. Round your answer to four decimal places.. Click here to see answer by stanbon(60771)

 Question 335959: A fair die is rolled and a card is chosen at random. What is the probability that that the number on the die matches the number on the card? Click here to see answer by jrfrunner(365)

 Question 335985: A random sample of 10 miniature Tootsie Rolls was taken from a bag. Each piece was weighed on a very accurate scale. The results in grams were 3.087 3.131 3.241 3.241 3.270 3.353 3.400 3.411 3.437 3.477 (a) Construct a 90 percent confidence interval for the true mean weight. (b) What sample size would be necessary to estimate the true weight with an error of ± 0.03 grams with 90 percent confidence? (c) Discuss the factors which might cause variation in the weight of Tootsie Rolls during manufacture. Click here to see answer by stanbon(60771)

 Question 336090: How many outcomes are possible when a coin is flipped seven times? Click here to see answer by stanbon(60771)

 Question 336075: find the critical value. assume that the test is two-tailed and that n denotes the number of pairs of date. n=80, a=0.05 Click here to see answer by stanbon(60771)

 Question 336073: Twelve out of the 144 shoe city stores sell childern's clothing. You write the names of all of the stores locations on cards select a card at random. What is the probability of not picking a store location that sell children's clothing? justify. please help! Click here to see answer by stanbon(60771)

 Question 336070: A bag contains 5 green, 3 red, 2 orange and 6 yellow skittles. How many green skittes must have been added to the bag so that the probability of randomly picking a green skittle is 2/3? Explain Click here to see answer by stanbon(60771)

 Question 336029: . A psychologist interested in political behavior measured the square footage of the desks in the official office of four U.S. governors and of four chief executive officers (CEOs) of major U.S. corporations. The figures for the governors were 44, 36, 52, and 40 square feet. The figures for the CEOs were 32, 60, 48, and 36 square feet. (a) Figure the means and standard deviations for the governors and for the CEOs. (b) Explain, to a person who has never had a course in statistics, what you have done. (c) Note the ways in which the means and standard deviations differ, and speculate on the possible meaning of these differences, presuming that they are representative of U.S. governors and large corporations’ CEOs in general Can someone please help me? I have been stuck on this for days....... Click here to see answer by stanbon(60771)

 Question 336130: The soccer team has jerseys numbered from 10 to 30. Everyone on the team gets a jersey and there are three left over. How many players are on the team? Click here to see answer by stanbon(60771)

 Question 336208: a customer enters a supermarket. the probability that they will buy bread is 0.6, the probability that they will buy milk is 0.5, and the probability that they will buy both is 0.3. What is the probability that they will buy either bread or milk or both? Click here to see answer by jim_thompson5910(29613)