# 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 622155: A sample of 4 telephones is selected from a shipment of 20 phones. There are 5 defective telephones in the shipment. How many of the samples of 4 phones do not include any of the defective ones? Click here to see answer by math-vortex(472)

 Question 622345: There are three green, three blue and three white marbles in a jar. What is the probability of drawing first a white marble and then a blue marble, without replacing the first marble into the jar? Click here to see answer by ewatrrr(10682)

 Question 622343: A bag has ten marbles in it. Three of them are green, one of them is red, five of them are yellow, and one of them is blue. If one marble is taken out of the bag randomly, what is the probability that it will either be green or red? Click here to see answer by ewatrrr(10682)

 Question 622341: A jar contains seven coins: a dime, 2 quarters, and 4 nickels. One coin is taken from the jar at random. What is the probability that the coin taken is a nickel? Click here to see answer by ewatrrr(10682)

 Question 622408: A bag contains 17 marbles - 6 blue, 7 red, and 4 green marbles. If four marbles are drawn randomly (without replacement), determine the probability that three of them are green Click here to see answer by ewatrrr(10682)

 Question 622404: The number of ways of selecting 2 boys or 2 girls from a group of 4 boys and 5 girls Click here to see answer by ewatrrr(10682)

 Question 622416: The number of ways of selecting 2 boys and 2 girls from a group of 4 boys and 5 girls Click here to see answer by ewatrrr(10682)

 Question 622403: The number of ways of selecting 2 boys and 2 girls from a group of 4 boys and 5 girls. Click here to see answer by ewatrrr(10682)

 Question 514842: A survey has been administered to random samples of respondents in each of five nations. For each nation, are men and women significantly different in terms of their reported levels of satisfaction? Respondents were asked, “How satisfied are you with your life as a whole?” Responses varied from 1 (very dissatisfied) to 10 (very satisfied). Conduct a test for the significance of the difference in mean scores. France Males Females Mean= 7.4 Mean=7.7 SD = .2 SD = .25 N= 1005 N=1234 What is the obtained value to the nearest hundredth? Click here to see answer by zamantha(1)

 Question 622551: 2. A shoe store’s records show that out of a 100 customers who made a purchase last week, 30 used credit cards to make payment. This morning 20 customers purchased shoes from the store. Find the probability that at least 12 of the customers used credit cards. a) Define the random variable b) What distribution will be used? c) Represent the question as a probability statement. d) Calculate the probability. Click here to see answer by solver91311(17077)

 Question 622636: The probability of an event E not occurring is 0.2. What are the odds in favor of E occurring? Click here to see answer by math-vortex(472)

 Question 622743: Given a binomial distribution with n = 125 and p = 0.04, would the normal distribution provide a reasonable approximation? Why or why not? Click here to see answer by ewatrrr(10682)

 Question 622724: suppose you roll two dice find the probability of not rolling a sum of 12 Click here to see answer by math-vortex(472)

 Question 622873: According to an Internet posting, 80% of adults enjoy drinking beer. If a group of 3 adults is selected at random, find the probability that none of them enjoy drinking beer. Place your answer, rounded to three decimal places, in the blank. Click here to see answer by ewatrrr(10682)

 Question 622939: I came across this question on the internet after reading about the recent Raytheon MATHCOUNTS competition. I guess there is a long way and a short way to solve the problem (the competition winner solved it in 19 seconds supposedly), and I was hoping you could show me both ways please. I am a very slow learner so I'd appreciate it if you don't skip too many steps when you show me the solution. Thank you in advance. A bag of coins contains only pennies, nickels and dimes with at least five of each. How many different combined values are possible if five coins are selected at random? Click here to see answer by richard1234(5390)

 Question 622904: Please, I need help solving this question. A company with 3,895 employees selects employees for random drug tests. Each employee is assigned a number between 1 and 3,895. The company uses a computer to randomly select employee numbers that range from 1 to 3,895. Find the probability of selecting a number greater than 2900. Thank you. Click here to see answer by nerdybill(7011)

 Question 622960: A quiz consisting of of four multiple-choice questions has four available options (a, b , c, and d) for each question. If a person guesses at every question, what is the probability of answering all questions correctly? Click here to see answer by mykasha(37)

 Question 623008: (need help)From the Data Bank, select a variable and compare the mean of the variable for a random sample of at least Steeler players weight with the mean of the variable for the random sample of at least 30 St louis players weight. Use a z test Steelers/St.LouisRams(weight) 215 210 195 185 180 185 240 209 246 235 287 242 305 315 300 306 245 260 311 195 305 285 202 220 196 230 185 212 196 184 235 230 288 239 290 311 187 280 248 196 293 270 298 220 212 199 193 225 233 189 203 225 226 295 297 300 335 304 193 255 258 280 245 210 264 206 216 215 193 229 243 242 213 300 224 305 295 305 302 255 202 295 190 225 300 185 201 250 200 200 210 226 246 345 250 315 330 186 282 195 208 290 192 240 Click here to see answer by mykasha(37)

 Question 623007: (NEED Help)From the Data Bank, select a variable and compare the mean of the variable for a random sample of at least 30 fotball players from the steelers with the mean of the variable for the random sample of at least 30 football players from St louis rams. Use a z test Data Below WEIGHT/Steelers St.LouisRams 215 210 195 185 180 185 240 209 246 235 287 242 305 315 300 306 245 260 311 195 305 285 202 220 196 230 185 212 196 184 235 230 288 239 290 311 187 280 248 196 293 270 298 220 212 199 193 225 233 189 203 225 226 295 297 300 335 304 193 255 258 280 245 210 264 206 216 215 193 229 243 242 213 300 224 305 295 305 302 255 202 295 190 225 300 185 201 250 200 200 210 226 246 345 250 315 330 186 282 195 208 290 192 240 Click here to see answer by mykasha(37)

 Question 622896: when treated with an antibiotic, 94% of all dolphins are cured of an ear infection. if 5 are treated, find the probability that exactly 3 are cured Click here to see answer by mykasha(37)

 Question 622898: There are 6 red marbles and 4 blue marbles in a jar. You remove one marble, and than remove another marble without replacing the first one. What is the probability that you remove 2 red marbles. Click here to see answer by mykasha(37)

 Question 622890: A decade-old study found that the proportion, , of high school seniors who believed that "getting rich" was an important personal goal was . A researcher decides to test whether or not that percentage still stands. He finds that, among the high school seniors in his random sample, believe that "getting rich" is an important goal. Can he conclude, at the level of significance, that the proportion has indeed changed? Perform a two-tailed test. Then fill in the table below. Carry your intermediate computations to at least three decimal places and round your answers as specified in the table. (If necessary, consult a list of formulas.) Quick Help How do I enter a symbol for Statistics? Click here to see answer by mykasha(37)

 Question 622970: A biopsychologist studies the role of the brain chemical serotonin in aggression. One sample of rats serves as a control group and recieves a placedo. A second sample of rats recieves a drug that lowers brian levels of serotonin. Then the researcher tests the animals by recording the number of aggressive responses each of the rats displays. the data are presented below: a. What are the null and alternative hypotheseses? b. Does the drug have a significant effect on aggression? use an alpha level of .05, two tailed. Low Serotonin N=4 M=22 SS-76 Control N=8 M=14 SS=164 Click here to see answer by mykasha(37)

 Question 622971: Can someone kindly check my answers for me? I would appreciate any help if my answers are not correct. Thank you. A probability experiment is conducted by first spinning the spinner below, then tossing a coin. The spinner has numbers 1,2,3,4,5, 6,7,8. What set represents the sample space? {H1,H2,H3,H4,H5,H6,H7,H8,T1,T2,T3,T4,T5,T6,T7,T8} Draw a tree diagram for the probability experiment. H T 1 2 3 4 5 6 7 8 1 2 3 4 5 6 7 8 {H1,H2,H3,H4,H5,H6,H7,H8, T1,T2,T3,T4,T5,T6,T7,T8} Click here to see answer by mykasha(37)

 Question 622987: Hi, My question is about a variant of the ball - urn problem. We have 8 black and 2 white balls. I take out ALL of them one after the other and line them up. I would like to know how likely it is that the 2 white ones are found at position e.g. 2 and 3 or any other 2 consecutive positions. There is a practical background like serial analysis behind this question. Ten sequential data points should contain 2 that are sticking out at a given position to meet certain requirements. This event should be better than chance. I'd appreciate your thoughts, Walter Click here to see answer by mykasha(37)

 Question 622983: e.Which of the following hypotheses concerning the mean difference between two populations cannot be tested by looking at a confidence interval for the mean difference? H0:1-2=0 H0:1-2=5 H0:1+2=0 Click here to see answer by mykasha(37)

 Question 622996: A probability experiment consists of spinning the spinner divided into 8 parts 1,2,3,4,5,6,7,8, and rolling a six-sided die. What is the probability of spinning an even number and then rolling an odd number greater than 2 Thank you. Click here to see answer by mykasha(37)

 Question 623074: Two cards are drawn from a standard deck of cards with replacement. What is the probability that the first is a King and the second is not a King? Click here to see answer by nerdybill(7011)

 Question 623077: Two cards are drawn from a standard deck of cards without replacement. What is the probability that the first is a King and the second is not a King? Click here to see answer by Alan3354(31538)

 Question 623199: If you toss two standard dice, what is the probability that you will get a 3 on at least one die? Express your answer as a common fraction. Click here to see answer by ewatrrr(10682)

 Question 623182: Please show me specific detailed answers to these question i got wrong on my test. Thankyou. (a)A password is 3-character long which only consists of upper case letters from A to N inclusively. Find the number of different passwords that can be created if each upper case letter cannot be used more than once. (b)A box contains four red, three black and two white balls. Three balls are randomly drawn without replacement. Find the probability that the third ball is black. Click here to see answer by ewatrrr(10682)

 Question 623216: A population has a mean of 300 and a standard deviation of 18. A sample of 144 observations will be taken. The probability that the sample mean will be between 297 to 303 is: Supposely the result is 0.8664 but i cant get the result for nothing... i get always 0.9545. How i get the other result? I'd be greatful for some answer... normally i dont get any on this site :( Thanks in advance Click here to see answer by ewatrrr(10682)

 Question 623218: Students who have completed a speed reading course have reading speeds that are normally distributed with a mean of 950 words per minute and a standard deviation equal to 220 words per minute. If two students were selected at random, what is the probability that they would both read at less than 400 words per minute? Click here to see answer by ewatrrr(10682)

 Question 623202: A population of size 1000 has a proportion of 0.5. therefore, the proportion and the standard deviation of the sample proportion for samples of size 100 are? Click here to see answer by ewatrrr(10682)

 Question 623170: A box contains blue and green balls in ratio 3:4.If there are 21 balls in the box and 2 balls are taken one after the other without replacement.What is the probability that the two balls are of the same colours? Click here to see answer by ewatrrr(10682)

 Question 623169: A box contains blue and green balls in ratio 3:4.If there are 21 balls in the box and 2 balls are taken one after the other without replacemen.What is the probability that the two balls are of the same colours? Click here to see answer by ewatrrr(10682)

 Question 623118: . A student is taking a 5 question True-False quiz but he has not been doing any work in the course and does not know the material so he randomly guesses at all the answers. a) What is the probability that he gets the first question right? b) What is the probability that he gets the first three questions right? c) What is the probability that he gets at least one question right? First of all, I don't understand the difference between Question a and Question c. Also, I read some other examples but I do not get yet on this website and my book, and still can not answer these questions. So far I have done this P= .5 since they are true and false. n= 10 since they are 10 question But I dont know how to use this data. help please!! Click here to see answer by Theo(3504)
 Question 623118: . A student is taking a 5 question True-False quiz but he has not been doing any work in the course and does not know the material so he randomly guesses at all the answers. a) What is the probability that he gets the first question right? b) What is the probability that he gets the first three questions right? c) What is the probability that he gets at least one question right? First of all, I don't understand the difference between Question a and Question c. Also, I read some other examples but I do not get yet on this website and my book, and still can not answer these questions. So far I have done this P= .5 since they are true and false. n= 10 since they are 10 question But I dont know how to use this data. help please!! Click here to see answer by jsmallt9(3296)