Tutors Answer Your Questions about Probability-and-statistics (FREE)
Question 452768: Suppose that you and your friend are part of a group of 14 potential jurors. If two people from this group are to be chosen at random for the last remaining seat on the jury, what is the probability that you and your friend are the two people chosen?
Click here to see answer by stanbon(57347)  |
Question 452695: The following table lists the probability distribution of the number of refrigerators owned by all families in a city. Study the distribution and answer the questions.
x 0 1 2 3
P(x) .02 .28 .61 .09
The probability that a family owns:
a. Exactly 3 refrigerators is: _______
b. At least 2 refrigerator is: _____
c. Fewer than 3 refrigerators is: _____
d. The mean of the distribution is = ______
e. The standard deviation of the distribution is = _____
Click here to see answer by robertb(4012)  |
Question 452916: The Department of Transportation maintains statistics for mishandled bags per 1000 passengers. In a prior year, Budget Airlines averaged 2.9 mishandled bags per 1000 passengers. What is the probability that in the next group of 1000 passengers Budget Airlines will have no mishandled bags?
Click here to see answer by stanbon(57347) |
Question 452914: A research company wishes to estimate, with 95% confidence, the proportion of people who have 3 television sets in the home. A previous study of 200 people shows that 30% of those interviewed had 3 TV's in the home. The company wants to be accurate within 4% of the true proportion. Find the minimum number of people this company must sample.
Click here to see answer by stanbon(57347) |
Question 452910: on a reality show a contestant must randomly choose enough people to go into a room so that the probability that at least one of those people has the same birthday (month and date ) as the contestant is greater than 50%. Time is of the essence sot the contestant doesnt want any more people than necessary. What number of people should the contestant gather?
use this method above to determine how many people would need to be in a room so that the probability of two of them having birthdays on the same day of the month is greater than 50%
Click here to see answer by stanbon(57347) |
Question 452900: A study of 200 commercial firms revealed the data below. What is the probability that a particular firm will have $1 million or more in income after taxes?
Income After Taxes Number of Firms
Under $1 million 102
$1 million up to $20 million 61
$20 million and more 37
Click here to see answer by stanbon(57347) |
Question 453028: The speed limit in the state of Ohio is 55 miles per hour. On a certain stretch of interstate highway the mean speed of traffic (as checked by radar) is 58 miles per hour with a standard deviation of 4 miles per hour. The speeds of vehicles on this section of highway are normally distributed.
What percentage of vehicles are exceeding the speed limit?
Above what speed are the top 5% of the speeders travelling?
Thanks so much for your help!
Click here to see answer by stanbon(57347) |
Question 453029: A cruise ship has 74% chance of having leftover rooms the week before the cruise. There are 25 cruise ships setting this month.
Is it possible to approximate this binomial distribution using normal approximation?
What is the mean and the standard deviation for this approximation?
What is the probability that exactly 20 cruise ships will have leftover rooms using the normal distribution?
Thank you!
How different is the normal approximation from the binomial distrution value? Calculate the probability that exactly 20 cruise ships will have leftoer rooms using the binomial method.
Click here to see answer by stanbon(57347) |
Question 452767: Out of the 200 insomniacs, 98 reported regularly watching The Late Show with David Letterman before they began to count sheep.Calculate the margin of error for a 78% confidence interval of the true proportion of insomniacs who regularly watch David Letterman before counting sheep.
A. 0.164
B. 0.056
C. 0.043
D. 0.136
Click here to see answer by stanbon(57347) |
Question 453102: I know that this question has been asked but I have a question about the 2 blue balls. Do they come into play at all in the equation?
an urn contains 12 balls identical in every respect except color. there are 3 red balls, 7 green balls, and 2 blue balls. you draw two balls from the urn but replace the first ball.
This is the answer that was listed. But I wonder how the blues play into the part.
3/12*7/12
21/144
7/48=.1458 or 14.58% ans
Click here to see answer by solver91311(16885)  |
Question 453289: If the probability of a certain team winning is 3/4, what is the probability that this team will win its first three games and lose the fourth? I'm not sure where to begin given my basic understanding of probability. Can you help?
Click here to see answer by robertb(4012) |
Question 453313: Creo has forgottent the last two digits on her four digit computer pass code. She cannot log on until she inputs the correct code. She remebers that all four digits are differnt from another and tthat the first 2 digits are 0 and 3. She input one possible code every two seconds . What is the maximum number of seconds it will take he to log on to her computer , assuming she tries no combination more than once
Click here to see answer by stanbon(57347) |
Question 453297: I have a statistics problem where I am suppose to find the mean, median, and sum of squared deviation for the following scores: 8, -5,7, -10, 5. I found the mean by adding up all the scores and then dividing by the numbers of scores. So the mean is M=1. My median was found by adding 5 + 1 and then divided by 2= 5.5. Finding the sum of squared deviations I'm at a lose. I know my formula is SS/N .I know N represents the total number of scores which is 5 but I'm not sure what SS is. Any assistance would be appreciated.
Click here to see answer by stanbon(57347) |
Question 453318: abelardo wants to create several different7-character screen names.he wants to use arrangements of the first 3 letters of his first name(abe) follwed by arrangements of 4 digits in 1984 the year of his birth how many ifferents screen names can he create this way ?
Click here to see answer by stanbon(57347) |
Question 453426: The time it takes to give a man a shampoo and haircut is normally distributed with mean 22 minutes and standard deviation 3 minutes. Customers are scheduled every 30 minutes.
(a)
What is the probability that a male customer will take longer than the allotted time? (Round your answer to 4 decimal places.)
Probability
(b)
If three male customers are scheduled sequentially on the half-hour, what is the probability that all three will be finished within their allotted half-hour times? (Round your answer to 4 decimal places.)
Click here to see answer by edjones(7569)  |
Question 453424: The length of a Colorado brook trout is normally distributed.
(a) What is the probability that a brook trout's length exceeds the mean? (Round your answer to 2 decimal places.)
Probability
(b) What is the probability that a brook trout's length exceeds the mean by at least 1 standard deviation? (Round your answer to 4 decimal places.)
Probability
(c) What is the probability that a brook trout's length exceeds the mean by at least 2 standard deviations? (Round your answer to 4 decimal places.)
Click here to see answer by edjones(7569) |
Question 453425: In a certain microwave oven on the high power setting, the time it takes a randomly chosen kernel of popcorn to pop is normally distributed with a mean of 140 seconds and a standard deviation of 25 seconds.
(1)
What percentage of the kernels will fail to pop if the popcorn is cooked for (Round your answers to 4 decimal places. Omit the "%" sign in your response.)
(a) Two minutes %
(b) Three minutes %
(2)
Determine the time that would be allowed in order to get the following percentage of the kernels popped. (Round your answers to 3 decimal places.)
(c) 95 percent seconds
(d) 99 percent seconds
Click here to see answer by edjones(7569) |
Question 453552: Suppose each of the numbers 1, 2, 3, 4, 5, 6, 7, 8, 9, and 10 is written on a separate poker chip and placed in a hat. If one of the chips is randomly selected, determine the probability that the chip selected will contain an odd number or a number less than five.
Click here to see answer by edjones(7569) |
Question 453594: Question 3
Find the mean, variance, and standard deviation of the binomial distribution with the given values of n and p. n = 90 p = .6
mean of a binomial distribution = np 90 * .6 = 54
q = 1-p 1- .6 = .4
variance = npq 54 * .4 = 21.6
Standard Deviation = sqrt(npq) = ( my answer does not come out correctly when I get to this part)
Click here to see answer by jim_thompson5910(28595) |
Question 453680: A bag contains yellow and red blocks, there are 4 more red blocks than yellow. When pulling two blocks out, one at a time, you can not replace the first block. What is an expression that represents the probability of pulling out a red block first, then a yellow block?
Thank you.
Click here to see answer by ilana(307) |
Question 453762: In the NASCAR racing industry ball bearings are automatically produced on a Kronar BBX machine and are known to be normally distributed. For one of the production lines, the mean diameter is set at 20.00 mm (millimeters). The standard deviation, over a long period of time, was computed to be 0.150 mm. What percent of the ball bearings on this line will have diameters of 20.27 mm or more?
Click here to see answer by edjones(7569) |
Question 453762: In the NASCAR racing industry ball bearings are automatically produced on a Kronar BBX machine and are known to be normally distributed. For one of the production lines, the mean diameter is set at 20.00 mm (millimeters). The standard deviation, over a long period of time, was computed to be 0.150 mm. What percent of the ball bearings on this line will have diameters of 20.27 mm or more?
Click here to see answer by stanbon(57347) |
Question 453763: "Suppose a system can continue to operate successfully if one or both of its components do not fail. Suppose the probability of component #1 failing is .065 and the probability of component #2 failing is .045. Assuming the component failure is independent of any other component failing, determine the probability the system operates successfully."
I didn't get very far before getting stuck, but it looks like the system can operate with one or both components operating successfully. There are 4 possible outcomes of component operation:
1: Component #1 and Component #2 both work
2: Component #1 works, Component #2 does not work
3: Component #1 does not work, Component #2 works
4: Neither Component #1 or Component #2 work.
The first three circumstances are the only possible situations where the system will operate successfully. But I don't know what to do next...
Click here to see answer by edjones(7569) |
Question 453775: The mean value of the amount of beverage injected into the bottles in a whiskey-bottling operation is known to be normally distributed with an average value of 750 milliliters (ml) and a standard deviation of 10 ml. What is the probability that you might randomly select a sample that lies between 745 ml and 748 ml?
Click here to see answer by stanbon(57347) |
Question 453714: I need some assistance with the following problem. My work doesn't look correct.
For the following scores find the (a) mean, (b) median, and (c) sum of the squared deviations. 3.0, 3.4, 2.6, 3.3, 3.2, 3.2
(a) mean
2.6, 3.0, 3.2, 3.3, 3.4, 3.5
Number of scores 6
Total: 19/6 M=3.17
(b) median
2.6, 3.0, 3.2, 3.3, 3.4, 3.5
6+1=7 divide by 2 = 3.5
(c) Sum of squared deviations
1st term: (2.6-3.17)= (-.57)^2= .3249
2nd term: (3.0-3.17)= (-.17)^2= .029
3rd term: (3.2-3.17)= (-.03)^2=.009
4th term: (3.3-3.17) (.13)^2=.169
5th term: (3.4-3.17)=(.23)^2=.0529
6th term:(3.5-3.17)=(.33)^2=.1089
Thank you for your help
Click here to see answer by stanbon(57347) |
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