Tutors Answer Your Questions about Probability-and-statistics (FREE)
Question 561061: hi,
the probability of two students failing is .1 where student A will fail .5 and student b will fail .2 , what is the probability that both students will pass? I know the answer is .4 please tell me how to calculate this.
thanks
Click here to see answer by richard1234(5390)  |
Question 278054: Quality Progress, February 2005, reports on the results achieved by Bank of America in improving customer satisfaction and customer loyalty by listening to the “voice of the customer.” A key measure of customer satisfaction is the response on a scale from 1 to 10 to the question: “Considering all the business you do with Bank of America, what is your over all satisfaction with Bank of America?” Suppose that a random sample of 350 current customers results in 195 customers with a response of 9 or 10 representing “customer delight.” Find a 95 percent confidece interval for the true proportion of all current Bank of America customers who would respond with a 9 or 10. Are we 95 percent confident that this proportion exceeds .48, the historical proportion of customer delight for Bank of America?
Click here to see answer by maxigirl(1) |
Question 561104: 1. a box containing 6 red balls and 4 green balls. how many ways can 2 balls be drawn at the time if
a. the balls are of any color?
b. in the balls are of the same color?
c. if the two balls are different color?
2. a sample of 12 students will be taken from a class with 26 girls and 15 boys. In how many ways can a sample be taken if
a. there must be equal number of boys and girls
b. gender is not a consideration
c. 2 girls are fixed elements and the rest are all boys
Click here to see answer by Edwin McCravy(8879)  |
Question 561102: a box containing 6 red balls and 4 green balls. how many ways can 2 balls be drawn at the time if
a. the balls are of any color?
b. in the balls are of the same color?
c. if the two balls are different color?
Click here to see answer by stanbon(57205) |
Question 560981: The distribution of certain test scores is a nonstandard normal distribution with a mean of 90 and a standard deviation of 2. What are the values of the mean and standard deviation after all test scores have been standardized by converting them to z scores
Click here to see answer by stanbon(57205) |
Question 560948: Following a brushfire, a forester takes core samples from the ten surviving Bigcone Douglas-fir trees in a test plot within the burn area, and a dendrochronologist determines the age of the source trees to be as follows (in years):
15 38 48 67 81 83 94 102 135 167
3. Calculate the sample mean and standard deviation for the age of Bigcone Douglas-fir trees based on the data above. If this accurately represents the population mean and standard deviation for the age of surviving Bigcone Douglas-fir trees in the burn area, what is the probability that a randomly selected surviving Bigcone Douglas-fir tree from the burn area will be 111 years old or less? Round to the nearest hundredth
Click here to see answer by stanbon(57205) |
Question 561458: In a probability experiment a painted cube is rolled once. One side of the cube is painted red, two sides are painted yellow, and three sides are painted green. Find the theoretical probability (P) of each event.
1) P (yellow)
2) P (green)
3) P ( red)
4) P ( yellow or green)
5) P (blue)
6) P ( red or yellow or green)
Click here to see answer by stanbon(57205) |
Question 561452: In a probability experiment a 1-6 number cube is rolled once. Find the theoretical probability (P) of each event. Express your answer as a fraction in simplest form.
1) P (2)
2) P ( 3 or 5)
3) P (odd number)
4) P ( 2, 3, or 4)
5) P ( prime number)
6) P (composite number)
Click here to see answer by stanbon(57205) |
Question 561438: Five separate awards are to be presented to selected students from a class of size 30.
a) How many different outcomes are possible if a student can receive any number of awards?
b) How many different outcomes are possible if each student can receive at most one award?
Click here to see answer by stanbon(57205) |
Question 561523: .A final exam in Math 160 has a mean of 73 with standard deviation 7.73. Assume that a random sample of 24 students is selected and the test score of the sample is computed. Assuming the scores are normally distributed, what percentage of sample means are less than 69
Click here to see answer by stanbon(57205) |
Question 561506: Use one of these words or phrases to complete each sentence: certain, impossible, very likely, not likely, more likely, less likely.
1) the probability of tossing a coin and getting an outcome of heads or tails is ______.
2) an outcome of 2 or 4 on a 1-6 number cube is ____ than an outcome of any odd number.
3) an outcome of tossing a coin and getting an outcome of tails is ___ than rolling a 1-6 number cube and getting an outcome of 3.
4) the probability of tossing a coin and getting an outcome of heads and tails is ___.
5) an outcome of an odd number on a 1-6 number cube is __ than an outcome of 3 or 5.
6) the probability of tossing a coin and getting an outcome of heads and tails is __ than the probability of flipping a coin ang getting an outcome of heads or tails.
7) it is ___ that peron was born during the month of February
8) it is ___ that a persons age is a one-digit or a two-digit number.
Click here to see answer by stanbon(57205) |
Question 561937: A stack of cards contains 7 hearts numbered 1 through 7, and 9 clubs numbered 1 through 9. If two cards are drawn at random with replacement, what is the probability of drawing a 2 of any suit on the first draw and the same card on the second draw?
Click here to see answer by stanbon(57205) |
Question 561912: In a scientific study there are 12 guinea pigs, 5 of which are pregnant. If 3 are selected at random without replacement, find the probability that none are pregnant. Enter your answer as a fraction.
I can find the probability that all are pregnant but I cant seem to be able to solve this problem. I would really appreciate if someone can guide me step by step how to solve it. Thank you, in advance =]
Click here to see answer by stanbon(57205) |
Question 562633: There are six positions available in the research department of a software company. Of the applicants, 15 are men and 10 are women.
In how many ways could 4 men and 2 women be chosen if each were equally qualified?
What is the probability that five women are selected if the positions are randomly filled?
Click here to see answer by stanbon(57205) |
Question 562613: 1. A sample space consists of 10 separate events that are equally likely. What is the probability of each?
2. On a true/false test, wht is the probability of answering a question correctly if you make a random guess?
3.On a multiple-choice test with five possible answers for each question, what is the probability of answering a question correctly if you make a random guess?
Click here to see answer by stanbon(57205) |
Question 562687: A group of 16 students are working together to study for a test. After the test, they calculated their mean score to be 91%. The entire class mean was 88% with a standard deviation of 4.43. Assuming you are working at 0.05 level of significance, what should you conclude? Choices are A. The students' average is significantly better than the whole class. B. The students' average is not significantly better than the whole class. C. We need the standard deviation of the student's grades. D. the z score is not the appropriate test to use.
I was calculating z scores, but I am stuck and becoming lost. Please help!
Click here to see answer by stanbon(57205) |
Question 562802: On-Time Airplane Arrivals. The greater Cincinnati airport led major U.S. airports in on-time arrivals in the last quarter of 2005 with an 84.3% on-time rate. choose 5 arrivals at random and find the probablitiy that at least 1 was not on time.
Click here to see answer by stanbon(57205) |
Question 562997: Finding Mean and Standard Deviation:
Let the random variable X represent the number of girls in a family of four children. Construct a table describing the probability distribution, them find the mean and standard deviation.
Could you help me with this problem please?
Thanks
Click here to see answer by stanbon(57205) |
Question 563087: if a box contains 4 red balls, 5 blue balls, and 6 green balls, suppose that they are selected one by one until a green ball is found. what is the probability that it is necessary to examine at least 6 balls?
what i've tried. obviously, there are 15 balls total, and by the combination formula, 15 nCr 6 (in TI-83 language, in English, 15 choosing 6) there are 5005 possible combinations when you choose 6 from a total of 15. I am just stumped on how to get the numerator to divide by 5005.
Any insight would be greatly appreciated. Thank you.
Click here to see answer by scott8148(6628)  |
Question 563291: I am struggling with several questions any help would be greatly appreciated I just cant seem to figure these out.
1) Two events A and B are ____________ if the probability that A or B occurs is the sum of the probability that A occurs with the probability that B occurs.
2)A correlation coefficient of 0.96 would mean that the values of x increase as the values of y decrease. True or False?
3) What is the value for for a 98% confidence interval when n=12?
A) 23.053
B) 24.725
C) 25.090
D) 24.278
Thank you in advance
John
Click here to see answer by stanbon(57205) |
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