# 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

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

 Question 359657: 7. How many green elements are required to make this a legitimate probability distribution if there are a total of 50 elements in this sample?x red blue orange brown green P(x) 0.20 0.20 0.32 0.18 Click here to see answer by Fombitz(13828)

 Question 359653: solve the probability density function f(x)= {2x-4} 2<= x<= 3, =0 otherwise find the median value and interquartile range of X Click here to see answer by Fombitz(13828)

 Question 359370: consider the experiment of selecting a card from an ordinary deck of 52 playing cards and A card with a multiple of 4 on it is drawn. Click here to see answer by Fombitz(13828)

 Question 359688: Please Help an english quiz contained two multiple choice questions that had three choices and five multiple choice questions with five choices. how many different ways is it possible to complete this test? thank you Click here to see answer by edjones(7569)

 Question 359692: ) A local charity sells 100 raffle tickets for \$20 each as part of a fund raiser. There is one Grand Prize of \$500, one First Prize of \$100, and 8 Second Prizes of \$50. Find the expected winnings per ticket sold Click here to see answer by edjones(7569)

 Question 359699: Please Help In a recent survey 64% of the cars entering the Maine turnpike at Kittery had out of state plates. Of those with out of state plates, 75% said that they were tourists. If one car is chosen at random, what is the probability that: a)The car has Maine plates? b)It has out of state plates but still does not contain tourists? c)It has out of state plates and tourists? thank you Click here to see answer by edjones(7569)
 Question 359699: Please Help In a recent survey 64% of the cars entering the Maine turnpike at Kittery had out of state plates. Of those with out of state plates, 75% said that they were tourists. If one car is chosen at random, what is the probability that: a)The car has Maine plates? b)It has out of state plates but still does not contain tourists? c)It has out of state plates and tourists? thank you Click here to see answer by ewatrrr(10682)

 Question 359703: Please Help:) It is known that 28% of American adults claim to be able to play a musical instrument. If twelve American adults are selected at random, what is the probability that: a. none of them plays an instrument? b.fewer than five of them play an instrument? c.more than five of them play an instrument? d.more than half of them do not play an instrument? Thank you Click here to see answer by edjones(7569)

 Question 359678: A test is composed of six multiple choice questions where each question has 4 choices. If the answer choices for each question are equally likely, find the probability of answering more than 4 questions correctly. Click here to see answer by edjones(7569)

 Question 359390: I was just wondering if someone could double check my work on this problem: A box contains 8 good parts and 4 defective parts. If a sample of 2 parts is drawn from the box at random (without replacement), what is the probability of each of the following: Two good parts are selected. (my answer 8/12 * 7/11 = 14/33 or 42%) Two defective parts are selected. (my answer 4/12 * 3/11= 1/11 or 9%) One good part is selected first, and then one defective part is selected second? (my answer 8/12 or 66% chance of good part first, 4/11 or 36% chance of defective part being chosen second 8/12 * 4/11 = 8/33 or 24% totalling a 24% chance) Exactly one defective part out of the two is selected. (my answer ?) Any input would be apprieciated! Click here to see answer by Fombitz(13828)

 Question 359724: 4. A company recruits personnel for its sales department on the basis of special tests designed to judge the potential of the candidates. The following table gives test scores and the mean daily sales for 9 executives. a. Fit a regression line of Y on X. b. Prepare a table of predicted values and residuals. Mean daily Score(Y) 34 39 30 33 36 38 45 41 48 Test Score (X) 59 69 50 56 64 66 77 73 83 Click here to see answer by Fombitz(13828)

 Question 359750: For a normal distribution, with a mean of 44 and a standard deviation of 6, what is the probability of randomly drawing a participant with a sore of 35? Click here to see answer by Fombitz(13828)

 Question 359869: A test is composed of six multiple choice questions where each question has 4 choices. If the answer choices for each question are equally likely, find the probability of answering 3 OR 4 questions correctly Click here to see answer by stanbon(57220)

 Question 359879: A 15-minute Oil and Lube service claims that their average service time is no more than 15 minutes. A random sample of 40 service times was collected, and the sample mean was found to be 16.4 minutes, with a sample standard deviation of 3.2 minutes. Is there evidence to support, or to reject the claim at the alpha = 0.01 level? Perform an appropriate hypothesis test, showing the necessary calculations and/or explaining the process used to obtain the results Click here to see answer by stanbon(57220)

 Question 359712: Please help me:0 A car battery is known by the manufacturer to last 65 months with a standard deviation of 4.5 months. a. If the manufacturer guarantees them for five years (60 months), what percentage of them will they have to replace? b. If the manufacturer does not want to replace more than 4% of the batteries, for how many months should they guarantee them (round to the nearest whole month)? thanks you :) Click here to see answer by stanbon(57220)

 Question 359892: A poll of U.S. health professionals revealed 82% would choose the same career. In a hypothesis test conducted at a level of significance of 5%, a P-value of 0.023 was obtained. Choose the best interpretation of the hypothesis test Click here to see answer by stanbon(57220)

 Question 359895: An engineering firm is evaluating their back charges. They originally believed their average back charge was \$1800. They are concerned that the true average is higher, which could hurt their quarterly earnings. They randomly select 40 customers, and calculate the corresponding sample mean back charge to be \$1950. If the standard deviation of back charges is \$500, and alpha = 0.05, should the engineering firm be concerned? Perform an appropriate hypothesis test, showing the necessary calculations and/or explaining the process used to obtain the results Click here to see answer by stanbon(57220)

 Question 359891: A shipment of 35 computers contains three that are defective. How many ways can a small business buy four of these computers and receive no defective ones? Click here to see answer by stanbon(57220)

 Question 359889: An engineering firm is evaluating their back charges. They originally believed their average back charge was \$1800. They are concerned that the true average is higher, which could hurt their quarterly earnings. They randomly select 40 customers, and calculate the corresponding sample mean back charge to be \$1950. If the standard deviation of back charges is \$500, and alpha = 0.01, should the engineering firm be concerned? Perform an appropriate hypothesis test, showing the necessary calculations and/or explaining the process used to obtain the results Click here to see answer by stanbon(57220)

 Question 359931: Say I tossed two dice 100 times and wrote down the values. Theoretical P(at least one 6 or a difference of four)= 5/36 about 13% Actual P(at least one 6 or a difference of four)= 12% Would I calculate the standard deviation of the data to get a value or use a binomial dist and get the theoretical standard deviation. Or better yet, what does the standard deviation tell me in regard to why my actual and theoretical are not the same? Click here to see answer by edjones(7569)

 Question 360012: If the proportion of women in a population is .53, what is the probability that of 12 people selected, 0 are women? Click here to see answer by robertb(4012)

 Question 360067: Construct a scatterplot for the (x, y) values below, and answer the following questions. You do NOT need to submit your scatterplot with your answer; however, show all other work. x y 1 7.0 2 13.0 3 19.0 4 25.0 5 31.0 - What would be the slope of this regression line? - Would the correlation between x and y be positive or negative? - How would you interpret these data in terms of linear regression? Click here to see answer by Fombitz(13828)

 Question 360068: In testing a new drug, researchers found that 20% of all patients using it will have a mild side effect. A random sample of 13 patients using the drug is selected. Find the probability that: (A) exactly three will have this mild side effect (B) at least five will have this mild side effect. Binomial Problem with n=13; p=0.20 Find the probability that exactly three will have this mild side effect P(x=3)=0.20^3 I am not sure if I am on the right track with this? Click here to see answer by ewatrrr(10682)

 Question 360219: A product has a mean life of 660 hours, and a standard deviation of 45 hours. A business buys 100 such products at random. What is the probability that the mean life of those 100 products would be greater than 650 hours? Click here to see answer by stanbon(57220)

 Question 360119: 2.42 ) Four candidates are seeking a vacancy on a school board . If A is twice as likely to be elected a B, and B and C are given about the same chance of being elected , while C is twice as likely to be elected as D , what are the probability that : a) C will win b) A will not win ? Click here to see answer by stanbon(57220)

 Question 360111: 2.92) IF five of a company's 10 delivery trucks do not meet emission standards and three of them are chosen for inspection , What is the probability that none of the trucks chosen will meet emission standards ? Click here to see answer by stanbon(57220)

 Question 360203: Here are the numbers of sales per day that were made by a telemarketer who worked four days before being fired: 1, 11, 9, 3. Assume that samples of size 2 are randomly selected with replacement from this population of four values. a. List all the possible samples and find the mean of each. b. Identify the probability of each sample, then create the sampling distribution of sample means. c. Find the mean of the sampling distribution. Click here to see answer by stanbon(57220)

 Question 360117: The probability that a one-car accident is due to faulty brakes is 0.04 , the probability that a one-car accident is correctly attributed to faulty brakes is 0.82 , and the probability that a one-car accident is incorrectly attributed to faulty brakes is 0.03 . What is the probability that : a) A one-car accident will be attributed to faulty brakes; b) A one-car accident attributed to faulty brakes was actually due to faulty brakes . Click here to see answer by edjones(7569)

 Question 360100: Of 200 students who took gym 160 passed the preliminary fitness assessment and 140 passed the final fitness assessment. 124 students passed both assessments. Let A represent the students who passed the preliminary fitness assessment and B represent those who passed the final fitness assessment. Use probability notation to describe and solve the following. 1. What is the probability that a student chosen at random passed the preliminary fitness exam? 2. What is the probability a student chosen at random passed the final fitness assessment? 3. What is the probability that a student chosen at random passed both fitness assessments? Click here to see answer by edjones(7569)

 Question 360277: A box contains five gold balls and two orange balls. A ball is selected at random, its color is recorded, and then it si replaced. A second ball is then selected at random and its color recorded. The outcome associated with this type of selection is an order pair (first draw, second draw). List the sample space for this experiment, where G denotes gold and O denotes orange. A) {(G,O)} B) {(G,O), (O,O),(G,G),(O,G)} C) {(G,G), (O,O)} D) {{G,O), (O,G)} Click here to see answer by stanbon(57220)

 Question 360290: If the results on a nationally administered university entry exam are normally distributed with a mean of 45 points and a standard deviation of 4 points, determine the following: (a) Describe the graph of this distribution (if you can do so, produce an electronic sketch of the graph to the right, otherwise adequately describe the distribution graph through its shape and horizontal scale values.) (b)Find the z-score for a single exam that had 35 points. Then find the z-score for one with 45 points. (c)If x represents a possible point-score on the exam, find P(x < 41). (d)Find P(40 < x < 50) and give an interpretation of this value. (e)Suppose a certain university requires one to score in the top 40% of all such scores to be admitted. What is the minimum number of points one must score on this exam for admission? Click here to see answer by neatmath(300)

 Question 360279: According to the insurance company, the probability that a woman will survive one year is 0.994, and the probability that she will die in one year is 0.006. If she buys a \$10,000 one-year term policy for \$100, what is the company's expected gain or loss? A) loss of \$40,00 B) gain of \$40.00 C) No gain or loss Click here to see answer by edjones(7569)

 Question 360241: A local medical research association proposes to sponsor a footrace. The average time it takes to run the course is 45.8 minutes with a standard deviation of 3.6 minutes. If the association decides to include only the top 25% of the racers, what should be the cut off time in the tryout run? Assume the variable is normally distributed. Would a person who runs the course in 40 minutes qualify? Click here to see answer by neatmath(300)

 Question 360393: Construct a scatterplot for the (x, y) values below, and answer the following questions. You do NOT need to submit your scatterplot with your answer; however, show all other work. ```X Y 1 -5 2 -10 3 =15 4 -20 5 -25 ``` Click here to see answer by Edwin McCravy(8880)

 Question 360426: Unfortunately, financial scam artists often prey on alder people. In a certain US state, 19% of people older than 65 have been a victom of some con artist. If a person over 65 from this state is chosen at random, what is the probability that person has been a victon of a con artist? Click here to see answer by ewatrrr(10682)

 Question 360425: I need help on how to do this binomial probability problem on a TI-84 calculator: use the fact that approximately 2% of people have blood type B-. consider a random sample of 850 students.what is the probability that at least 13 students have blood type B-? Click here to see answer by Edwin McCravy(8880)

 Question 360556: in a business class there are 12 men and 8 women 4 students are randomly selected to present a topic what is the probability that 3 out of 4 are men Click here to see answer by stanbon(57220)

 Question 360474: A university is trying to select from a group of students who have volunteer to help out at an alumni reunion event. The university plans to pick 4 students at random from this group of 6 in-state and 4 out-of state students. what is the probability that all the students selected will be in-state students? Click here to see answer by edjones(7569)

 Question 360472: A survey-taker asks the age of each person in a random sample of 20 people. X is the age for the individuals. Does X have a binomial distribution? A. Yes. B. No, because the observations are not all independent. C. No, because there are more than two possible outcomes for each observation. D. No, because there is not a fixed number of observations. Click here to see answer by edjones(7569)

 Question 360514: what percentage of dolphins live up to 17 years old 20 years old 25 years old 40 years old and 50 years old? Click here to see answer by checkley77(12569)

 Question 360489: Three six sided dice are thrown and produce a random set of numbers eg 1 4 6 = 11. Now a second set of three six sided dice are thrown. Before we worry about the sum total of the second set here is the question. Before any dice are thrown including the first set what is the probability that the sum total for both dice set A will be equal to the sum total of dice set B before we know the result of A. MIke Manttan sets will be exactly equal. Not just 11 but any number Click here to see answer by Edwin McCravy(8880)

 Question 360586: For the following statement, write the null hypothesis and the alternative hypothesis. Then, label the one that is the claim being made. An employment agency claims that the mean salary for graduating teachers is \$42,000. Click here to see answer by stanbon(57220)

 Question 360572: 60% of all people are eligible for jury duty and favor capital punishment. A jury of 12 is to be randomly selected. What is the probability that 10 of the 12 jury members are in favor of capital punishment? Click here to see answer by stanbon(57220)

 Question 360292: I do not see how the answer is 50%....when calculating the scores less than 100 with a mean of 100 and standard deviation of 20. I understand the rule and how to plot the numbers and I calculated the standard deviation for the left and right, but I still cannot see how the answer is 50%. Thanks Click here to see answer by scott8148(6628)

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