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Question 597168: A supplier of components to an electronic industry makes a sophisticated product which sometimes fails immediately it is used. He controls his manufacturing process so that the proportion of faulty products is supposed to be only 5%. Out of 400 supplies in a batch, 26 prove to be faulty. Verify the manufacturer’s claim. Use 0.05 level of significance.
Click here to see answer by stanbon(57967)

Question 597178: In a certain population of students, 15% of all the students have full-time jobs. You plan to take a large random sample of 140 students.
Find the standardized score (Z) corresponding to the sample proportion (p-hat) you computed above.
Click here to see answer by stanbon(57967)

Question 597175: At a certain university, 15% of all the students have full-time jobs. You plan to take a large random sample of 140 students.
Use the Rule for Sample Proportions to describe the distribution of all possible sample proportions (p-hat values) for this situation. To do this, first find the mean and standard deviation of all sample proportions (show this work). Then, referring to the picture below, label the marked points by giving the appropriate proportion values for the seven blanks under the graph (using the entry boxes provided).
You are expected to enter your answers for this problem using leading zeros and exactly two (2) decimal places (if not, the computer might consider correct answers to be incorrect).
(Thus, if your answer is one-half, you'll enter 0.50...if your answer is one-third, you'll enter 0.33...if your answer is zero, you'll enter 0.00...etc.)
Mean =
St. Dev. =
Z = -3 -> p-hat =
Z = -2 -> p-hat =
Z = -1 -> p-hat =
Z = 0 -> p-hat =
Z = 1 -> p-hat =
Z = 2 -> p-hat =
Z = 3 -> p-hat =

Click here to see answer by stanbon(57967)

Question 597204: As part of a monthly inspection at a hospital, the inspection team randomly selects reports from eight of the 84 nurses who are on duty. (a) What is the probability that none of the reports selected will be from the ten most experienced nurses on duty? [Answer is: 0.364] (b) What is the probability that all of the reports selected will be from the 20 least experienced nurses on duty? [Answer is: 0.0000029]
I have the answers, I just don't know how to get to them.
Click here to see answer by scott8148(6628)

Question 597307: find odds against getting a spade from deck of cards
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Question 597307: find odds against getting a spade from deck of cards
Click here to see answer by solver91311(17077)

Question 597302: a set of data is distributed with a mean of 98 and a standard deviation of 5. What is the probability that a value from the data is less than 88?
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Question 597285: Ayuh Fishin' Kamps on Moosehead lake advertises that 80% of its guests manage to catch fish every day they are there. A random sample taken last summer showed that 58 out of 80 guests did catch at least one fish every day.
A. What is the null hypothesis?
B. Is this 1-tailed or 2-tailed test?
C. What is the critical value for Z(alph=0.05)?
D.Do we reject or fail to reject the null hypothesis?
Click here to see answer by stanbon(57967)

Question 597397: Imagine you havean urn in which there are 100 balls, 30 of balls are blue. You take a random sample of 6,what are the probability that in your sample there are 0,1,2,3,4,5 and 6 blue balls respectively
Click here to see answer by edjones(7569)

Question 597404: A bag contains 5 nickels, 7 dimes, and 2 quarters. If you draw 3 coins at random from the bag, without replacement, what is the probability that you will get a nickel, a quarter, and a nickel, in that order?
Click here to see answer by edjones(7569)

Question 597355: a container has 5 blue balls, 7 red balls, and 4 green balls. if 3 balls are drawn, without replacement, what is the probability that all three will be green?
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Question 597377: Suppose that the scores on the final exam for this course are normally distributed with a mean of 55 and a standard deviation of 10. I decide to “curve” student grades by adding 30 points to each student’s final exam grade.
What is the new mean and new standard deviation?
Is it fair to curve by adding 30 to each grade? Why or why not
Click here to see answer by stanbon(57967)

Question 597648: A box is filled with red cards, yellow cards, and brown cards. A card is chosen at random from the box. What is the probability that the card is not yellow?
Write your answer as a fraction in simplest form.

Click here to see answer by math-vortex(472)

Question 597753: A number cube labeled with numbers 1,2,3,4,5, and 6 is tossed. What are the odds for the cube showing a 4?
Click here to see answer by jim_thompson5910(28715)

Question 597761: A basketball player hits three-point shots 44% of the time. If she takes 4 shots during a game, what is the probability that she hits all 4 shots?
Click here to see answer by jim_thompson5910(28715)

Question 597772: A bag contains 8 apples and 6 oranges. If you select 7 pieces of fruit without looking, how many ways can you get exactly 6 apples?
Can you please show me how to work this problem.... I think it is 8!/6! = 56???
Click here to see answer by scott8148(6628)

Question 597806: An order of award presentations has been devised for 7 people: Jeff, Karen, Lyle, Maria, Norm, Olivia, and Paul...
In how many ways can teh first award be presented to Karen and the last to Lyle?
Click here to see answer by jim_thompson5910(28715)

Question 297529: The marketing manager of a large supermarket chain would like to use shelf space to predict the sales of pet food. For a random sample of 12 similar stores, she gathered the following information regarding the shelf space, in feet, devoted to pet food and the weekly sales in hundreds of dollars.
Store 1 2 3 4 5 6
Shelf Space 5 5 5 10 10 10
Weekly Sales 1.6 2.2 1.4 1.9 2.4 2.6
Store 7 8 9 10 11 12
Shelf Space 15 15 15 20 20 20
Weekly Sales 2.3 2.7 2.8 2.6 2.9 3.1
1-Compute the value of the sample correlation coefficient between weekly sales and shelf space.
2-Is the correlation between weekly sales and shelf space significant at the .01 level of significance?
3-What is the estimated regression equation?

Click here to see answer by ao0703839(1)

Question 525038: In a random sample of 60 computers, the mean repair cost was $150 with a standard
Deviation of $36.
(a) Construct the 99% confidence interval for the population mean repair cost.
(b) If the level of confidence was lowered to 90%, what will be the effect on the confidence interval

Click here to see answer by merlin694(1)

Question 597923: Use the given degree of confidence and sample data to construct a confidence interval for the population mean u. Assume that the population has a normal distribution n=12, x=21.3, s=6.3, 99%
Click here to see answer by stanbon(57967)

Question 597887: how many meters are 7.2 yards rounded to the nearest hundredth

Click here to see answer by Alan3354(31529)

Question 597928: A laboratory tested 71 chicken eggs and found that the mean amount of cholesterol was 230 milligrams with σ = 10.4 milligrams. construct a 95% confidence interval for the true mean cholesterol content, u, of all such eggs
Click here to see answer by jim_thompson5910(28715)

Question 597944: If a sample size of 121 is chosen then what would be the actual degrees of freedom?
Click here to see answer by jim_thompson5910(28715)

Question 597514: Please show me specific detailed answers to these question i got wrong on my test. Thankyou.
the sizes of leaves( in cm2) of a tree follow a normal distribution with a mean of 12.9cm2 and a standard deviation of 2.4cm2 .find the probabilities of the following events.
the size of a randomly selected leaf is greater than (15/20)cm2.
average size of 36 randomly selected leaves is greater than (15/20)cm2.
suppose you roll two fair dice for 20 times and let y be the number of times that the random variable x gets a value greater than or equal to 4.
find p(x>4)
what is the probability that y is greater than zero?
find the mean variance and standard deviation of the random variable Y.
Click here to see answer by fire120(1)

Question 598203: What is the probability of observing a a value more then .75 from a standard normal distribution?
I got 1-.7734
What is the probability of observing a number less then 5 or more than 10 from a normal distribution with mean 9 and standard deviation 2?
Click here to see answer by stanbon(57967)

Question 598197: Consider a binomial experiment with 20 trials and probability 0.45 on a single trial. Use an approximatation to the normal distribution to find the probability of exactly 10 successes. Round your answer to the thousandths place.
Click here to see answer by stanbon(57967)

Question 598289: Please help me find the probability of less than 3 of 6 using BINOMIST. Can you help please?
Click here to see answer by solver91311(17077)

Question 598424: NO CALCULATIONS REQUIRED!!! Just tell whether or not you reject the null hypothesis and then write a vali conclusion.
1. when 200 convicted embezzelers were randomly selected, the mean length of prison was 22.1 months and the standard deviation was found to be 8.6 months. a candidate running for governor on a platform of tougher treatment for convicted criminals claims that the mean sentence for embezzelers is less than 2 years. Use significance level .05.
P-Value = .0010
Click here to see answer by jim_thompson5910(28715)

Question 598395: Find the probability of the event.
3 heads or 2 tails appearing in 3 tosses of a coin.
Click here to see answer by edjones(7569)

Question 598375: A class is given a list of 20 study problems from which 10 will be chosen as part of an upcoming exam. A given student knows how to solve 15 of the problems. Find the probablility that the student will be able to answer (a) all 10 of the questions on the exam, (b) exactly 8 questions on the exam, and (c) at least 9 questions on the exam.
Something I for (a) was
probability that he will know the answer to one question=15/20=.75
(.75)^10=.056
the answers were
(a).016 or 21/1292 (b) .348 or 225/646 (c) .152 or 49/323
Click here to see answer by stanbon(57967)

Question 598649: Find the area under the normal distribution curve to the right of z=3.24.
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Question 598528: Given the linear correlation coefficient r and the sample size n, determine the critical values of r and use your finding to state whether or not the given r represents a significant linear correlation. Use a significance level of 0.05.
r = 0.616, n = 25
When I completed the question, I got Critical values: r = ±0.396, no significant linear correlation but the correct answer is Critical values: r = ±0.396, significant linear correlation. So how do you determine if its a linear correlation?
Click here to see answer by richard1234(5390)

Question 598869: Suppose the National Hurricane Center forecasts that hurricanes will hit the strike area with a .95 probablity. Answer the following questions:
1. What probability distribution does this follow?
2. What is the probability that 10 hurricanes reach landfall in the strkie area?
3. What is the probability at least one of 10 hurricanes reaches land outside the strike area?
Click here to see answer by stanbon(57967)

Question 598850: drawing cards three cards are drwn from a deck without replacement.find the probabilities.
a. all are jacks.
b.all are clubs.
c. all are red cards
Click here to see answer by stanbon(57967)

Question 598854: 2 vases 1st vase red flwr(3), white flwr.(3), pink flwr. (3),
2nd Vase red flwr,(5),white flwr.(4), pink flwr. (3),
What are chances of picking same color flw. if one picks 1 flw. from each vase blindfolded.
Please tell me how you do this ? TIA
Click here to see answer by stanbon(57967)

Question 598865: There are 16 members on a board of directors. If they must elect a chairperson, a parliamentarian, a secretary, and a treasurer, how many different slates of candidates are possible?
Click here to see answer by stanbon(57967)

Question 598971: A standardized test has a mean of 600 and a standard deviation of 75. If 1000 students took the test and their scores approximate a normal curve, how many scored between 600 and 750?
Click here to see answer by stanbon(57967)

Question 598999: A pizza restaurant manager claims that the average home delivery time for their pizza is no more than 25 minutes. A random sample of 49 home delivery pizzas was collected. The sample mean was found to be 26.5 minutes and the standard deviation was found to be 4 minutes. Is there evidence to reject the manager’s claim at alpha =.05? Perform an appropriate hypothesis test, showing the necessary calculations and/or explaining the process used to obtain the results.
Click here to see answer by stanbon(57967)

Question 598992: On a certain day the chance of rain is 80% in San Fran and 30% in Sydney. Assume that chances are independent in the two cities. What is the probability that it will not rain in either city?
Click here to see answer by stanbon(57967)

Question 598959: find the margin of error for n=800 given each sample of size n.
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Question 598844: A decade-old study found that the proportion, p , of high school seniors who believed that "getting rich" was an important personal goal was 75%. A researcher decides to test whether or not that percentage still stands. He finds that, among the 215 high school seniors in his random sample, 175 believe that "getting rich" is an important goal. Can he conclude, at the 0.01 level of significance, that the proportion has indeed changed?
Perform a two-tailed test
Null Hypothesis: Ho
Alternative Hypothesis: H1
Type of Test Statistic:
The Value of the Test Statistic:
The two critical values at the 0.01 level of significance
Can we conclude that the proportion of high school seniors who believe that "getting rich" is an important goal has changed?
Click here to see answer by stanbon(57967)

Question 599031: A bag contains 30 marbles with 18 blues ones and 12 green ones. If you reach into the bag and draw out marbles one at a time until you have three in your hand, what is the probability that they are all green?
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Question 599029: A combination lock uses 2 letters and 3 digits. If repetition is permitted in the numbers but not the letters, how many different combinations would be possible?

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Question 599028: A coin is flipped and a fair 8-sided die is rolled. What is the probability of getting a tail and a 7?

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