# 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 393771: What happens to the t-distribution as the number of degrees of freedom increases? Click here to see answer by robertb(4012)

 Question 393634: If 9% of all calculators are defective, find the mean, variance and standard deviation of a lot of 500 calculators. Click here to see answer by robertb(4012)

 Question 394210: Please! help me understand mean ,exactly,atmost,neither, thank you so much Find probability if a coin is tossed 5 time P(0 tails) P(exactly 1 tail) P(at most 2 tails) P(at least 4 tails) Click here to see answer by stanbon(57342)
 Question 394210: Please! help me understand mean ,exactly,atmost,neither, thank you so much Find probability if a coin is tossed 5 time P(0 tails) P(exactly 1 tail) P(at most 2 tails) P(at least 4 tails) Click here to see answer by josmiceli(9676)

 Question 394217: Use a little algebra on the z-score formula to yield an expression for x instead of z. Click here to see answer by ewatrrr(10682)

 Question 394214: An angle has mean of 19° and standard deviation of 8°. If a value from this distribution is chosen at random, what is the probability that it will be between 19° and 24°? Click here to see answer by ewatrrr(10682)

 Question 394231: normally distributed population with mean of 19 and standard deviation of 8. What is the percentile rank of 17 in this distribution? Click here to see answer by ewatrrr(10682)

 Question 394259: molly has 8 scarves 12 hats and 5 coats in her closet how many possible outerwear combinations consisting of one scarf one hat and one coat can she make? Click here to see answer by stanbon(57342)

 Question 394260: stan was hoping to participate in a darts tournament that requires a scoring average of 200 and above. if stan has a 192 average after the first 5 games, what score does he need in the sixth and last game to qualify? Click here to see answer by TeishaRenee(14)

 Question 394263: diana has to sell boxes of cookies for her cub eagle troop. yesterday she sold 2/5 of the total number of boxes and today she sold 8 boxes. if her total for the 2 days was 45% of the total number of boxes she promised to sell. how many more does she need to sell? Click here to see answer by ewatrrr(10682)

 Question 394344: draw 2cards from a 52 standard deck of cards, let A=1st card is ace, let B=2nd card is spade. are A and B independent? what is p(a), p(b), p(a and b)? Click here to see answer by solver91311(16885)

 Question 394509: A cribbage hand consists of six cards. How many of the hands have 3 kings? Click here to see answer by edjones(7569)

 Question 394625: In today's business world, computer viruses can be lethal to the operations of a company. Suppose a local business has 38 laptop computers and, unknown to the company, that eight of these are infected with the deadly OUCH disease. The CEO of the company is making a big presentation at a major client and has randomly selected two of the laptops to use during the presentation. Find the probability that both of the computers selected for the presentation are infected by the OUCH virus. Click here to see answer by edjones(7569)

 Question 394628: At a plant, 20% of all produced parts are subject to a special electronic inspection. It is known that any produced part which was inspected electronically has no defects with probability 0.95. For a part that was not inspected electronically, this probability is only 0.7. A customer receives a part and finds defect in it. What is the probability that this part went through an electronic inspection? Click here to see answer by edjones(7569)

 Question 394631: Find each probability if a die is rolled 4 times P(exacty one 3) P(exacty three 3s) P(at most two 3s) P(at least 3s) Click here to see answer by edjones(7569)

 Question 394636: There are 8 action, 3 comedy, and 5 children's DVDs on a shelf. Suppose two DVDs are selected at random from the shelf. Find each probability P(2 action DVD) if no replacement occurs P(a comedy DVD, then children's DVD) if no replacement occurs Click here to see answer by edjones(7569)

 Question 394622: 10)A computer program is tested by 5 independent tests. If there is an error, these tests will discover it with probabilities 0.1, 0.2, 0.3, 0.4, and 0.5, respectively. Suppose that the program contains an error. What is the probability that it will be found g. by at least one test? h. by at least two tests? i. by all five tests? Click here to see answer by robertb(4012)

 Question 394620: 4.Under good weather conditions, 80% of flights arrive on time. During bad weather, only 30% of flights arrive on time. Tomorrow, the chance of good weather is 60%. What is the probability that your flight will arrive on time? Click here to see answer by robertb(4012)

 Question 394626: 8.A computer assembling company receives 24% of parts from supplier X, 36% of parts from supplier Y, and the remaining 40% of parts from supplier Z. Five percent of parts supplied by X, ten percent of parts supplied by Y, and six percent of parts supplied by Z are defective. If an assembled computer has a defective part in it, what is the probability that this part was received from supplier Z? Click here to see answer by robertb(4012)

 Question 394621: 5.Three computer viruses arrive as an email attachment. Virus A damages the system with probability 0.4. Independently of it, virus B damages the system with probability 0.5. Independently of A and B, virus C damages the system with probability 0.2. What is the probability that the system gets damaged? Click here to see answer by jrfrunner(365)

 Question 394618: 3.Among employees of a certain firm, 70% know C/C++, 60% know Java, and 50% know both languages. What portion of programmers a. does not know Java? b. does not know Java and C/C++? c. knows C/C++ but not Java? d. knows Java but not C++? e. If someone knows Java, what is the probability that he/she knows C/C++? f. If someone knows C/C++, what is the probability that he/she knows Java? Click here to see answer by jrfrunner(365)

 Question 394723: Sandy and Claude are playing a game in which there are 5 tiles in a bag, numbered 1 through 5. The game is played by the players taking turns pulling out a tile without replacing it. A player wins if they pull out the tile numbered "3". If Sandy goes first, what is the probability that she will win? choose the answer and explain the reason to choose your response 50% 45% 75% 60% Click here to see answer by jrfrunner(365)

 Question 394616: Suppose that after 10 years of service, 40% of computers have problems with motherboards (MB), 30% have problems with hard drive (HD), and 15% have problems with both MB and HD. What is the probability that a 10-year old computer still has fully functioning MB and HD? Click here to see answer by jrfrunner(365)

 Question 394731: A pizza shop advertises that they have 8 toppings, and they sell large, medium, and small pizzas. On a small pizza, you must choose 3 different toppings. On a medium pizza, you must choose 4 different toppings, and on a large, you must choose 5 different toppings. How many different pizzas can they make? Choose the answer and explain the reason to choose your response 475 219 182 657 Click here to see answer by jrfrunner(365)

 Question 394742: A computer program is tested by 3 independent tests. When there is an error, these tests will discover it with probabilities 0.2, 0.3, and 0.5, respectively. Suppose that the program contains an error. What is the probability that it will be found by at least one test? Click here to see answer by jrfrunner(365)

 Question 347956: Several territories and colonies today are still under the jurisdiction of another country. France holds the most with 16 territories, the United Kingdom has 15, the United States has 14, and several other countries have territories as well. Choose 3 territories at random from those held by France, the United Kingdom, and the Untied States. What is the probability that all 3 belong to the same country? Click here to see answer by Redlegj(1)

 Question 394810: Given that P(A)= 2/9, what are the odds in favor of A occurring? Given that P(A)= 1/36, what are the odds against A occurring? Click here to see answer by richard1234(5390)

 Question 394817: for a special price one may choose three kind of deli meats, two kinds of cheese and one type of bread. if there are eight choices of meat, four choices of cheese, and five choices of bread, how many different sandwiches with three meats and two cheese will be possible? Click here to see answer by stanbon(57342)

 Question 394805: Do students at various universities differ in how sociable they are? Twenty-five students were randomly selected from each of three universities in a region and were asked to report on the amount of time they spent socializing each day with other students. The result for University X was a mean of 5 hours and an estimated population variance of 2 hours; for University Y,M = 4, S^2 = 1.5 ; and for University Z,M = 6, S^2 = 2.5 . What should you conclude? Use the .05 level. (a) Use the steps of hypothesis testing, (b) figure the effect size for the study; and (c) explain your answers to parts (a) and (b) to someone who has never had a course in statistics. Click here to see answer by jrfrunner(365)

 Question 394836: You are told that E(X)=8 and var(X)=4. What are the expected values and variances of the following expressions: a. Y= 3X-2 b. Y= 0.6X-4 c. Y= X/4 d. Y= aX+b, where a and b are constants e. Y= 3X^2+2 Click here to see answer by stanbon(57342)
 Question 394836: You are told that E(X)=8 and var(X)=4. What are the expected values and variances of the following expressions: a. Y= 3X-2 b. Y= 0.6X-4 c. Y= X/4 d. Y= aX+b, where a and b are constants e. Y= 3X^2+2 Click here to see answer by robertb(4012)

 Question 394838: what is difference between population data and sample data?? Click here to see answer by robertb(4012)

 Question 394623: 7.A spyware is trying to break into a system by guessing its password. It does not give up until it tries 1 million different passwords. What is the probability that it will guess the password and break in if by rules, the password must consists of j. 6 different lower-case letters k. 6 different letters, some may be upper-case, and it is case-sensitive l. any 6 letters, upper- or lower-case, and it is case-sensitive m. any 6 characters including letters and digits Click here to see answer by edjones(7569)

 Question 394887: An examination consists of 10 questions.A student must answer only one of the first two questions and only six of the remaing ones.How many choice of questions dose the student have? F)112 G)56 H)44 J)30 The key is G Click here to see answer by edjones(7569)

 Question 394888: Write an equation expressing the volume of a box made from a paper 12" x 15" from which a square with side length x is cut from each corner.Graph on your calculator the equation and find the maximum volume possible. i dont get how u graph it? Click here to see answer by mananth(12270)

 Question 394923: Two cards drawn in succession from a standard deck of cards without replacement.What is the prbability that both cards are greater than 2 and less than 9? Click here to see answer by Edwin McCravy(8909)

 Question 394924: While shooting arrows, William tell can hit an apple 9 out of 10 time.What is the probability that he will be hit exactly 4 out of 7 time? Click here to see answer by ewatrrr(10682)

 Question 394921: A munber is drawn at random from at hat that contain all the numbers from 1 to 100 .What is the prbability that the number is less than 16? Click here to see answer by ewatrrr(10682)

 Question 394949: Suppose you draw 2 cards from a deck of 52 cards. a) What is the probability that both cards are spades? b) What is the probability that at least one card is a spade? Click here to see answer by stanbon(57342)

 Question 394954: A coin is tossed 5 times. Calculate the following probabilities: a) Head appears on the 1st toss. b) Head appears on both the first and second tosses. c) Head appears once during the 5 tosses. d) Head appears more than twice during the 5 toss. Click here to see answer by stanbon(57342)

 Question 394926: A mail oder computer company offer a choice of 4 amounts of memory,2 size of hard driver, and 2 size of monitor .How many differenct systems are available on a customer? F)8 G)16 H)32 J)64 Click here to see answer by checkley79(3050)