# 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 270412: Using the following probability distribution for "Numbers of Cars sold" determine the expected value and standard deviation. Number of cars sold Probability 5 .15 8 .3 11 .33 17 .22 Click here to see answer by stanbon(57347)

 Question 270418: Billy has 10 books, but he only has space for 6 on his bookshelf. How many different arrangements (order does not matter) of the books can Billy make? Click here to see answer by stanbon(57347)

 Question 270422: Maggie is applying to college. There are only two outcomes for each application. It is either accepted or rejected. Each application she sends has a 0.70 probability of being accepted. If Maggie applies to 10 colleges, what is the probability that more than 8 of the applications will be accepted? What is the expected value for "number of acceptances?" Click here to see answer by stanbon(57347)

 Question 270415: For a normal probability distribution with a mean of 240 and a standard deviation of 40, calculate the following: a. The probability that an observation will fall between 240 and 300. b. The probability that an observation will fall between 195 and 240. c. The probability that an observation will be less than 260. d. The probability that an observation will fall between 180 and 220. Click here to see answer by stanbon(57347)

 Question 270410: A class has 15 students. Four of these students will be chosen to complete a special group project. How many different groupings (order does not matter) of 4 students can be created from this class of 15? Click here to see answer by stanbon(57347)

 Question 270406: Meredith has 20 shirts, 5 skirts, and 4 pair of shoes. How many different outfits (consisting of one shirt, one skirt and one pair of shoes) can she make? Click here to see answer by stanbon(57347)

 Question 270404: A shipping department will deliver a product in one, two, three or four days. The probability of delivery in one day is 0.18. The probability of delivery in two days is 0.27. The probability of delivery in three days is 0.48. What is the expected number days of delivery? Click here to see answer by stanbon(57347)

 Question 270462: How many license plates are possible to make if (a) digits and letters can be repeated, (b) and digits and letters cannot be repeated. a) 4 digits followed by 2 letters b)6 digits followed by 3 letters Click here to see answer by papugai(18)

 Question 270470: please help me solve this problem: if three fair coins are tossed, what is the probability of getting at least two heads? Click here to see answer by Greenfinch(383)

 Question 270454: Two cards will be drawn at once from a normal 52-card deck. What is the probability that both cards are Hearts? Click here to see answer by Greenfinch(383)

 Question 270486: A class has 29 students, of which 5 are seniors. How many committees of size 5 can be selected if at least one member of each committee must be a senior? Click here to see answer by stanbon(57347)

 Question 270478: if a deck has 53 cards, it contains 4 cuits (hearts,dimonds,clubs, and spades) of 13 cards each, where 10 are numbers cards and 3 face cards (jack, queen, king) a)how many different 6-card hands are possible if order does not matter? b) how many different 6-card hands can be dealt with all face cards sif order does not matter? c)How many 7-card hands can be dealt with no faces if order does not matter? Click here to see answer by stanbon(57347)

 Question 270600: Can someone please help me answer the following question? Thank you. Find the number of successes x suggested by the given statement. 5. Among 660 adults selected randomly from among the residents of one town, 30.2% said that they favor stronger gun-control laws. 6. Among 1400 randomly selected car drivers in one city, 8.29% said that they had been involved in an accident during the past year. Click here to see answer by stanbon(57347)

 Question 270624: Jessie has 5 short sleeves shirts, 8 long sleeve shirts, and 4 turtle neck shirts in her drawer..If she draws out 1 shirt, puts it on her bed, then draws out another shirt, which shows the probability that Jessie will draw out a turtleneck first, then a short sleeve shirt second? Click here to see answer by edjones(7569)

 Question 270637: Haley was told that her systolic blood pressure reading of 123 was in the 56th percentile for people aged 16-24. Interpret its meaning. Click here to see answer by stanbon(57347)

 Question 270646: At a certain non-profit organization, % of employees are college graduates and % of employees have more than ten years of experience. If % of the organization's employees are either college graduates or have more than ten years of experience (or both), what is the probability that a randomly selected employee will have more than ten years of experience and be a college graduate? Click here to see answer by stanbon(57347)

 Question 270692: Jeffrey wrote 1 on 1 slip of paper, 2 on 2 slips of paper, 3 on 3 slips of paper, 4 on 4 slips of paper, 5 on 5 slips of paper and 6 on 6 slips of paper.lf he draws 1 slip of Paper at random, what is Probability of getting an odd number? A 1/2 b 2/5 c 3/4 d 5/6 e 3/7 Click here to see answer by stanbon(57347)

 Question 270667: Should we estimate the common population standard deviation s by just averaging the two sample standard deviations? What if the first sample is of size 10 but the second sample is of size 100? Would you want to weight the corresponding sample standard deviations equally? Which sample standard deviation, s1 or s2, would you “trust” more? Click here to see answer by stanbon(57347)

 Question 270623: Can you help me with this question: Determine the approximate probability that a sample average (x-bar) taken from some population with the mean = 50 and standard deviation = 4 exceeds 50.6, where the sample size is 100? Click here to see answer by stanbon(57347)

 Question 270708: In each parts (a)-(c), we have given a likely range for the observed value of a sample proportion p. Based on the given range, identify the educated guess that should be used for the observed value of p to calculate the required sample size for a prescribed confidence level and margin of error. a. 0.4 to 0.7 b. 0.7 or greater c. 0.7 or less d. In each of parts (a)-(c), which observed values of the sample proportion will yield a largin margin of error than the one specified if the educated guess is used for the sample size computation? Click here to see answer by stanbon(57347)

 Question 270732: A survey of Amazon.com shoppers reveals the following probability distribution of the number of books per hit: X 0 1 2 3 4 5 6 7 P(X) 0.328 0.2 0.073 0.088 0.028 0.02 0.01 0.253 What is the probability that an Amazon.com visitor will buy eight books? Click here to see answer by stanbon(57347)

 Question 270730: Approximately 11% of people are left-handed. If two people are selected at random, what is the probability of the following events? A. P(Both are right-handed) = B. P(Both are left-handed) = C. P(One is right-handed and the other is left-handed) = D. P(At least one is right-handed) = Click here to see answer by stanbon(57347)

 Question 270597: Can someone please help me answer the following question? Thank you. Determine whether the samples are independent or dependent. 1. The effectiveness of a new headache medicine is tested by measuring the amount of time before the headache is cured for patients who use the medicine and another group of patient who use a placebo drug. 2. The effectiveness of a new headache medicine is tested by measuring the intensity of a headache in patients before and after drug treatment. The data consist of before and after intensities for each patient. 3. The effect of caffeine as an ingredient is tested with a sample of regular soda and another sample with decaffeinated soda. 4. The accuracy of verbal responses is tested in an experiment in which individuals report their heights and then are measured. The data consist of the reported height and measure height for each individual. Click here to see answer by stanbon(57347)

 Question 270761: Based on the information given for each of the following studies, decide whether to reject the null hypothesis. For each, give the Z-score cutoff (or cutoffs) on the comparison distribution at which the null hypothesis should be rejected, the Z score on the comparison distribution for the sample score, and your conclusion. Assume that all populations are normally distributed Population A 70 4 74 .05 1 B 70 1 74 .01 2 C 70 2 76 .01 2 D 72 2 77 .01 2 E 72 2 68 .05 1 Click here to see answer by stanbon(57347)

 Question 270524: what is a permutation and can you give example Click here to see answer by stanbon(57347)

 Question 270805: A population has a mean of 50 and a standard deviation of 7. You select a random sample of 36. Compute the following: The value for which there is a .025 probability that the sample mean will be greater than. Click here to see answer by stanbon(57347)

 Question 270877: how do you find the answer to the problem two cards are drawn from a standard 52 deck card deck. what is the probability of drawing an ace and a face card Click here to see answer by rfer(12660)

 Question 270994: A box contains 3 red marbles, 6 blue marbles, and 1 white marble. The marbles are selected at random, one at a time, and are not replaced. Find the probability. Click here to see answer by stanbon(57347)

 Question 270975: You are choosing a computer password. The password has 3 letters followed by 3 digits. a. How many passwords are possible if the letters must be uppercase? b. How many passwords are possible if no letter or digit can be repeated and the letters have to be lowercase? Click here to see answer by stanbon(57347)

 Question 271054: A player rolls 3 dice, what is the probability that only even numbers are rolled? Click here to see answer by rfer(12660)

 Question 271056: Im so confused, I don't even know where to start! they seem like the same question..please help : (! 1.) 100 units are shipped,the probabilty that one is defective is .2, you select 12 at random, what is the probabilty 3 are defective? 2.)A shipment has 20 bad and 80 good units, you pick 12 at random, what is the probabilty 3 are defective? Click here to see answer by stanbon(57347)

 Question 271097: in a battleground state, 36% of all voters are republicans. Assuming that there are only two parties - Democrat and Republican, if two voters are randomly selected for survey, what is the probability that they are both Republicans? Click here to see answer by stanbon(57347)

 Question 271043: Bob May Deno Sri Pat Alexis Scott Aretha Jen Ben New battery 45 41 53 40 43 43 49 39 41 43 Old battery 52 34 40 38 38 44 34 45 28 33 A new cell phone battery is being considered as a replacement for the current one. Ten college student cell phone users are selected to try each battery in their usual mix of “talk” and “standby” and to record the number of hours until recharge was needed. Click here to see answer by stanbon(57347)

 Question 271098: the height of the rocket in feet above the ground after t seconds is modeled by the equation h = 60t - 16tsquared. how long was the rocket in the air before it returned to the ground? Click here to see answer by scott8148(6628)

 Question 271154: 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 expectaion Click here to see answer by Edwin McCravy(8909)

 Question 271159: A 65 year old woman takes out a \$100,000 term life insurance policy. The company charges an annual premium of \$520. Estimate the company’s expected profit on such policies if the mortality tables indicate that only 2.6% of women age 65 die within a year. Click here to see answer by stanbon(57347)

 Question 271158: A carnival game is played as follows: You pay \$2 to draw a card from an ordinary deck of 52 playing cards. If you draw an ace, you win \$5. You win \$3 if you draw a face card (Jack, Queen, King) and \$10 if you draw the seven of spades. If you pick anything else, you lose your \$2. On average, how much money can the operater expect to make per customer? Click here to see answer by stanbon(57347)

 Question 271157: A census by the county dog control officer found that 18% of homes kept one dog as a pet, 4% had two dogs, and 1% had three or more. If a salesman visits two homes selected at random, what’s the probability that he encounters a. no dogs? b. some dogs? c. dogs in each home? d. more than one dog in each home? Click here to see answer by stanbon(57347)

 Question 271226: in a basket there are 25 red ball, 25 white balls, and 25 blue balls the probability of drawing 2 red balls in a row is 1/3 . true or false . i think its true but not sure and would like a way to figure it out . Click here to see answer by stanbon(57347)

 Question 271215: In a group of 30 pupils, 20 are girls and 10 are boys. From these 30 pupils, 5 are chosen at random. In how many ways may they be chosen? And find the probability that there are exactly 3 girls in the group of 5 chosen. Click here to see answer by stanbon(57347)

 Question 271285: Can someone please help me with this question? Thank you. A restaurant that delivers pizza wants to be sure that the delivery times remain consistent regardless of whether they have 1 or 2 delivery drivers working. Use a 0.10 significance level to determine whether or not the mean delivery times for the two different levels of staffing are essentially the same. You may assume the populations are normally distributed and that the samples are independent. 1 Driver 2 Drivers n1 = 28 n2 = 41 x-bar1 = 19.2 x-bar2 = 23.7 s1 = 5.38 s2 = 5.89 Identify each of the following. 16. The justification for normality in this situation. 17. The null and alternative hypotheses appropriate for this test.(To match the correct answer you will need to take 1 – 2.) 18. The calculated value of the test statistic. (To match the correct answer you will need to take 1 – 2.) 19. The critical-value needed for this test. 20. The decision reached by this test. Click here to see answer by stanbon(57347)

 Question 271306: In a large university, 15% of the students are female. If a random sample of twenty students is selected, a. what is the probability that the sample contains exactly four female students? b. what is the probability that the sample will contain no female students? c. what is the probability that the sample will contain exactly twenty female students? d. what is the probability that the sample will contain more than nine female students? e. what is the probability that the sample will contain fewer than five female students? f. what is the expected number of female students? Click here to see answer by stanbon(57347)

 Question 271290: A bag contains 17 balls numbered 1 through 17. What are the odds in favor of selecting a ball that has an even number? Click here to see answer by Edwin McCravy(8909)

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