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Tutors Answer Your Questions about Probability-and-statistics (FREE)
Question 236227: 6. Dewey, Cheetum, and Howe is a law firm that handles divorce cases. A previous study showed that in 34% of the time, their client got everything that was requested in the initial divorce papers. How many divorce proceedings would they have to survey to construct a 99% confidence interval for the true proportion of their clients get everything that they wanted in the divorce? If this interval is high enough, it would be a great advertising piece of information.
I have no idea where to start please help me.
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Question 236120: a manufacturer purchases two machines A and B .the probability that A will last five years is 4/5 and the probability that B will last five years is 3/4 find the probability that atleast one machine will last for five years
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Question 236064: A card is drawn from an ordinary deck of 52 cards, and the result is recorded on paper. The card is then returned to the deck and another card is drawn and recorded. Find the probability that the following occurs.
Only the first card is a club
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Question 236066: A card is drawn from an ordinary deck of 52 cards, and the result is recorded on paper. The card is then returned to the deck and another card is drawn and recorded. Find the probability that the following occurs.
Only the first card is a club
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Question 236031:
Can you PLEASE help me with this homework problem?? I appreciate any help you can give!
Table I
White Black Hispanic Asian Foreign Total
Dept. 1. 4 0 1 1 2 8
Dept. 2. 2 4 1 1 0 8
Dept. 3. 1 2 3 1 1 8
Dept. 4. 4 0 1 1 2 8
Dept. 5. 3 2 1 0 2 8
Total. 14 8 7 4 7 40
Table II
Female Male Total
Black 6 2 8
White 6 8 14
Hispanic 3 4 7
Asian 2 2 4
Foreign 5 2 7
Total 22 18 40
From Table 1: What is the probabilty of choosing a White employee from Dept. 2 and then a Hispanic employee from Dept. 3?
What is the probability of choosing a Foreigner or an Hispanic both from Department 5?
From Table 2: What is the probability of choosing a Black male or a Foreign male?
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Question 235963: I have answered some of these but am not for sure if they are correct, the others, I am not for sure. Thanks in advance
1. Decide whether the random variable is discrete or continuous.
a.The number of bottles of water drunk in Florida in August 2008
Discrete
b.The number of wasps in the lab test nest
Discrete
c.The height of sophomores in a required US History class at Ridgemont High in 2008
Continuous
d.The number of players on the Washington Redskins
Discrete
e.The speed of cars starting in the Darlington 500 in 2008
Continuous
2. Decide whether the distribution is a probability distribution. If it is not a probability distribution, identify the property that is not satisfied.
x P(x)
1 0.200
2 0.238
3 0.245
4 0.307
No it is not a probability distribution. It does not equal 1.
0.200 + 0.238 + 0.245 + 0.307 = 0.99
Section 4.2: Binomial Probability
4. In a local college, 60% of the math majors are women. Fifteen math majors are chosen at random. (1 points each)
a. What is the probability that exactly 6 are women?
b. What is the probability that 5 or less women are selected?
c. What is the probability that 10 women are selected?
d. Find the mean
e. Find the variance 2
5. A multiple choice test has 20 questions with each having 4 possible answers with one correct. Assume a student randomly guesses the answer to every question. (2.5 points each)
a. What is the probability of getting exactly 11 correct answers?
b. What is the probability of getting less than 9 correct answers?
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Question 235378: A factory worker places 86 newly created circuits on a shelf to be checked for quality. of these 6 will not work correctly. Suppose that she is asked to randomly select 2 circuits, without replacement. what is the chance that both circuits she selects will be defective? approximate to the nearest ten thousandth.
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Question 235920: A decade-old study found that the proportion of high school seniors who felt that "getting rich" was an important personal goal was 66%. Suppose that we have reason to believe that this proportion has changed, and we wish to carry out a hypothesis test to see if our belief can be supported. State the null hypothesis Ho and the alternative hypothesis H1 that we would use for this test.
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Question 235921: Suppose that a researcher is interested in estimating the mean systolic blood pressure,u, of executives of major corporations. He plans to use the blood pressures of a random sample of executives of major corporations to estimate u. Assuming that the standard deviation of the population of systolic blood pressures of executives of major corporations is 25 mm Hg, what is the minimum sample size needed for the researcher to be 90% confident that his estimate is within 5 mm Hg of u?
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Question 235408: The US Mint selects ten pennies from the production line to test the hypothesis that the mean weight of each penny is at least 6 grams. The normally-distributed weights (in grams) of these pennies are as follows: 6, 6, 8, 5, 9, 5, 9, 2, 3, 8. Assume = 0.01.
· State the null and alternate hypotheses
· Calculate the sample mean and standard deviation
· Determine which test statistic is appropriate (z or t), and calculate its value.
· Determine the critical value(s).
· State your decision: Should the null hypothesis be rejected?
I submitted this question on yesterday and did not get a response. I would like to thank you tutor for all of your hard work.
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Question 235409: I need your help in working this problem out. Thank you very much...
A watch manufacturer creates watch springs whose properties must be consistent. In particular, the standard deviation in their weights must be no greater than 2.0 grams. Fifteen watch springs are selected from the production line and measured; their weights are 1, 4, 8, 7, 1, 5, 1, 4, 1, 4, 3, 9, 1, 3, and 2 grams. Assume = 0.01.
· State the null and alternate hypotheses
· Calculate the sample standard deviation
· Determine which test statistic is appropriate (chi-square or F), and calculate its value.
· Determine the critical value(s).
· State your decision: Should the null hypothesis be rejected?
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Question 235847: In a college 30% students fail in Physics, 25% fail in Mathematics and 10% students fail in both. One student is chosen at random. What is the probability that
a) He fails in Mathematics if he has failed in Physics
b) He fails in Physics if he has failed in Mathematics.
c) He fails in Physics or Mathematics.
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Question 235413: Two groups of ten sprinters run 100 meters. The times required by sprinters in the first group are as follows:
12.0 12.9 10.1 14.6 11.9 11.3 13.0 12.9 13.3 10.0
The times required by sprinters in the second group are as follows:
11.6 12.5 12.3 10.2 16.3 17.0 19.1 18.7 12.3 16.4
Assuming that = 0.02, test the hypothesis that the means of the two populations are equal.
· State the null and alternate hypotheses
· Calculate the mean and standard deviation for each group
· Calculate the value of the test statistic.
· Determine the critical value(s).
· State your decision: Should the null hypothesis be rejected?
Thank you so very much for helping with this problem. I really do appreciate all of your hard work.
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Question 235411: I submitted this question on yesterday and did not get a response. I would like to thank the tutor for helping me on this problem.
A telephone survey gives 670 consumers two choices: Do they prefer Coke or Pepsi? Exactly 158 of those surveyed state that they prefer Coke. Assuming that = 0.10, test the hypothesis that the proportion of the population that prefers Coke is 50%.
· State the null and alternate hypotheses
· Calculate the sample proportion
· Calculate the value of the test statistic.
· Determine the critical value(s).
· State your decision: Should the null hypothesis be rejected?
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Question 235513: i have a question in the grouped data in statistics , they asking the probability that an emloyee . taken at random , earns more than 20000 pounds , total workers are 68 and they have group which interval is between 15000-24.999 . plzzzzzz help meeeeee
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Question 235541: A car battery manufacturer introduces a new technique to increase the life of the battery. 25 batteries were tested and got a mean life of 4.6 years with a standard deviation of 0.70 years. Construct a 90% confidence interval for the mean life of the new battery.
THX
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Question 235546: a manufacture of tv tubes has for many years used a process giving a mean tube life of 4900 hrs and a standard deviation of 1200 hours.
A new process is tried to see if it will increase the life significantly. A sample of 100 new tubes gave a mean life of 5000 hrs. Is the new process better than the old process at 1% level of significant? Construct hypotheses test it and interpret the result.
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Question 235577: a miniature golf course offers a free game to golfers who make a hole-in-one on the last hole.Last week, 56 out of 270 golfers made a hole-in-one on the last hole.Find the experimental probability that a golfer makes a hole-in-one on the last hole.please round your answer to two decmial places.
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Question 235550: The apollo space craft program lasted from 1967 to 1972 and incl 13 missions. The missions lasted from as little as 7 hrs to as long as 301 hrs. The duration of each flight is listed below:
9-195-241-301-216-260-7-244-192-147-10-295-142-
Is this dataset a sample or a population?
find the mmean and median of the flight time?
Find the range and quartile range of the flight times.
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Question 235547: Tthe mean amount purchased by each customer at a casino is 23.50 euros. The population is positively skewed and the standard deviation is not known. A MARKETING REseARCHER TOOK A sample of 50 customers. If the standard deviation of the sample is 5 euros, what is the likelihood that the sample mean is greater than 22.5 but less then 25 euros
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Question 235379: the fm radio stations with high signal strength in new orleans breaks down into the following categories:
hip hop 2
religious 6
country 2
rock 3
talk radio 2
other 5
if someone driving in new orleans tuned to a fm station at random, what would be the chance he would get a relirious or talk radio station? give in fraction at lowest terms.
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Question 235316: An oil drilling company knows that it costs $25,000 to sink a test well. If oil is hit, the income for the drilling company will bve $425,000. If only natural gas is hit, the income will be $125,000. If nothing is hit, there will be no income. If the probability of hitting oil is 1/40 and the probability of hitting gas is 1/20, what is the expectation for the drilling company? Should the company sink the test well.
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Question 235129: The pretzel pack company advertized that their pretzels weigh 2.5 ounces. The weights are normally distributed with mean 2.5 ounces and standard deviation 0.15 ounces. For a pretzel pack selected at random find the probabilty that it weighs less than 2.2 ounces and find the probability that it weighs more than 2.8 ounces.
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Question 235276: A factory worker places 86 newly created circuits on a shelf to be checked for quality. Of these, 6 will not work correctly. Suppose that she is asked to randomly select two circuits, without replacement, from the shelf. What is the chance that both circuits she selects will be defective? Approximate the soulution to the nearest ten thousandth.
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Question 235267: A bag contains 16 yellow marbles, 6 green marbles, and 7 red marbles. What is the chance of drawing a yellow marble? If a yellow marble is drawn the first time and then a second marble is drawn without replacement, what is the probability of drawing a second yellow marble. Give solution in reduced fraction form, separated by a comma.
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Question 235035: What is the probability that a 89% foul shooter will make at least 2 shots in a basketball game?
I know it is some sort of conditional probability, but I have now idea on what formula I need to use to solve it and my book is not very helpful.
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Question 235126: Ed earned 88 on his math midterm and 84 on his english midterm. In his math class the mean score was 75 with standard deviation 8. In his english class the mean score was 73 with standard deviation 5. Convert each score to a standard score, then find which was the higher score relative to the rest of the class.
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Question 235136: The life span of one species of a maple tree is normally distributed with mean 20 years and standard deviation 2.3 years. If one tree is choosen at random, what is the probability it will live 21 years or longer? What is the probability that the average lifetime of 9 such trees will be 21 years or more?
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