Showing 17–32 of 42 results

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A program for generating random numbers on a computer is to be tested. The program is instructed to generate 100 singledigit integers between 0 and 9.
$4.00$3.00Question: A program for generating random numbers on a computer is to be tested. The program is instructed to generate 100 singledigit integers between 0 and 9. The frequencies of the observed integers were as follows. At the 0.05 level of significance, is there sufficient reason to believe that the integers are not being generated uniformly?
Integer 0 1 2 3 4 5 6 7 8 9 Frequency 12 6 8 8 14 10 6 12 13 11 (a) Find the test statistic. (Round your answer to two decimal places.)
(b) Find the pvalue. (Round your answer to four decimal places.)

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A large supermarket carries four qualities of ground beef. Customers are believed to purchase these four varieties with probabilities of 0.13, 0.16, 0.13, and 0.58, respectively, from the least to most expensive variety.
$4.00$3.00Question: A large supermarket carries four qualities of ground beef. Customers are believed to purchase these four varieties with probabilities of 0.13, 0.16, 0.13, and 0.58, respectively, from the least to most expensive variety. A sample of 482 purchases resulted in sales of 46, 151, 88, and 197 of the respective qualities. Does this sample contradict the expected proportions? Use α = .05.
(a) Find the test statistic. (Give your answer correct to two decimal places.)
(b) Find the pvalue. (Give your answer bounds exactly.)
____< p < ____ 
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Consider a Poisson distribution with a mean of three occurrences per time period. (a) Write the appropriate Poisson probability function f(x)
$5.00$4.00Question:
Consider a Poisson distribution with a mean of three occurrences per time period.
(a) Write the appropriate Poisson probability function f(x)
(b) What is the expected number of occurrences in four time periods?
(c) Write the appropriate Poisson probability function to determine the probability of x occurrences in four time periods f(x)
(d) Compute the probability of three occurrences in one time period. (Round your answer to four decimal places.)
(e) Compute the probability of twelve occurrences in four time periods. (Round your answer to four decimal places.)
(f) Compute the probability of nine occurrences in three time periods. (Round your answer to four decimal places.)

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In a box of 12 light bulbs, it is known that 5 of them are defective. That is, 5 are defective
$3.00$2.00Question: In a box of 12 light bulbs, it is known that 5 of them are defective. That is, 5 are defective and 7 function properly. We select 2 bulbs from the bag at random, without replacement. Find the probability they both function properly. Show work. Round your answer to 3 decimal places.

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Barbara is a quality control inspector at a shoe factory. At the end of each day, she checks
$2.00$1.00Question: Barbara is a quality control inspector at a shoe factory. At the end of each day, she checks the number of imperfections found in sneakers. The table below represents the probability density function for the random variable X, t imperfections found in sneakers per day. Find the standard deviation of X. Round the final answer to two decimal places
x P(X=x) 0 1/4 2 1/4 4 1/4 7 1/4 
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Suppose a baker claims that the average bread height is more than 15cm. Several of this customers do not believe
$3.00$2.00Question: Suppose a baker claims that the average bread height is more than 15cm. Several of this customers do not believe him. To persuade his customers that he is right, the baker decides to do a hypothesis test. He bakes 10 loaves of bread. The mean height of the sample loaves is 17 cm with a sample standard deviation of 1.9 cm. The heights of all bread loaves are assumed to be normally distributed. The baker is now interested in obtaining a 95% confidence interval for the true mean height of his loaves. What is the lower bound to this confidence interval? cm (round to 2 decimal places) What is the upper bound to this confidence interval? decimal places) cm (round to 2 decimal places)

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The probability that a train leaves on time is 0.90. The probability that this train both leaves on time
$2.00$1.00Question: The probability that a train leaves on time is 0.90. The probability that this train both leaves on time and arrives on time is 0.75. If the train leaves on time, then what is the probability that is also arrives on time?.

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A recent issue of AARP Bulletin reported that the average weekly pay for a woman with a high school diploma
$4.00$3.00Question : Hypothesis Testing
A recent issue of AARP Bulletin reported that the average weekly pay for a woman with a high school diploma was $520. Suppose you would like to determine if the average weekly pay for all working women is significantly greater than that for women with a high school diploma. Data providing the weekly pay for a sample of 50 working women are available in the Excel file (Weekly Pay). Formulate the null and alternative hypotheses and conduct the appropriate test. What is your conclusion?
Weekly Pay
582 320 290 542 678 596 760 565 772
333 685 800 619 697 557 804 687 691
759 599 696 950 750 657 675 498
633 753 627 614 569 617 736 712
629 553 679 548 679 1230 565 533
523 641 667 570 598 648 587 424

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The waiting time(in minutes) for customers at a driveinbank
$2.00$1.00Question: The waiting time(in minutes) for customers at a driveinbank is an exponentially distributed random variable. The average(mean) time a customer waits is 4 minutes. What is the probability that a customer waits more than 5 minutes?

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Last month the waiting time at the drive through window of a fastfood restaurant was 3.7 minutes. The franchise has installed
$3.00$2.00Question : Last month the waiting time at the drive through window of a fastfood restaurant was 3.7 minutes. The franchise has installed a new process intended to reduce waiting time. After the installation, a random sample of 64 orders is selected. The sample mean waiting time is 3.57 minutes with a sample standard deviation of 0.8 minutes. At a 5% level of significance, is there sufficient evidence that the population mean waiting time is now less than 3.7 minutes? What is your conclusion?

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Ben is interested in flirting. He wants to know what kinds of people
$10.00$8.00Question: Ben is interested in flirting. He wants to know what kinds of people are likely to be good (and bad) at flirting. He thinks that selfconfidence will be correlated with flirting ability, but he’s not sure which way it will go. High selfconfidence should make for good flirters, but if people are too selfconfident, it might hurt their flirting performance. So he gives a number of students a selfconfidence measure (Y) and then watches them try to flirt with people at an offcampus bar (X). Both scales range from 1 (low) to 7 (high). He records the following scores:
SelfConfidence (X) Flirting (Y) 4 5 6 3 6 5 7 6 6 7 3 1 6 4 2 3 3 2 3 4  a) Compute the correlation for these scores. (SHOW YOUR WORK! Use as much space as necessary.)
 b) What does this correlation tell us about the relationship between selfconfidence and flirting ability?
 c) What is Ben’s alternative hypothesis?
 d) What is Ben’s null hypothesis?
 e) What is the coefficient of determination for these scores?
 f) How did you compute the coefficient of determination?
 g) How many degrees of freedom are there in this example?
 h) How did you compute the degrees of freedom? Should Ben perform a onetailed or twotailed test? Why?
 i) Assuming α = .05, what is the critical value for this example?
 j) Is the correlation you computed statistically significant? YES or NO
 k) How do you know whether or not the correlation is statistically significant?

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A tire manufacturer produces tires that are believed to have a mean life of at least 25,000 miles when
$4.00$3.00Question: A tire manufacturer produces tires that are believed to have a mean life of at least 25,000 miles when the production process is working correctly. Based on past experience, the population standard deviation of the lifetime of the tires is 3,500 miles. Assume a level of significance for testing of 5%, and a random sample of 100 tires:
A) What would be the consequences of making a Type II error in this problem?
B) Compute the Probability of making a Type II error if the true population mean is 24,000 miles 
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A machine that fills cans of Mountain Lightning is supposed to put 12 ounces of beverage in each can. The variance of the amount in each can is 0.01.
$2.00$1.00Question: A machine that fills cans of Mountain Lightning is supposed to put 12 ounces of beverage in each can. The variance of the amount in each can is 0.01. The machine is moved to a new location, which has previously been shown to alter the machine settings. Determine whether the variance has changed following the move based on the following sample of the fills of 10 Mountain Lightning cans.
12.18 11.77 12.09 12.03 11.87 11.96 12.03 12.36 12.28 11.85 
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In the Health ABC Study, 547 subjects owned a pet and 1971 subjects did not. Among the pet owners, there were 300 women
$5.00$4.00Question: In the Health ABC Study, 547 subjects owned a pet and 1971 subjects did not. Among the pet owners, there were 300 women; 982 of the nonpet owners were women. Find the proportion of pet owners who were women. Do the same for the nonpet owners. (Be sure to let Population 1 correspond to the group with the higher proportion so that the difference will be positive. Round your answers to three decimal places.)
Give a 95% confidence interval for the difference in the two proportions. (Do not use rounded values. Round your final answers to three decimal places.)

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Given set A contains the elements (a, b, c, d, e, f) and set B contains the elements (e, f, g, h, i, j) in a world where elements (a, through n) exist
$3.00$2.00Given set A contains the elements (a, b, c, d, e, f) and set B contains the elements (e, f, g, h, i, j) in a world where elements (a, through n) exist as shown in the diagram below
what are the elements of: ?
Select one:
 Elements (a, b, c, d, g, h, i, j)
 Elements (a, b, c, d, k, I, m, n)
 Elements (e, f, k, I, m, n)
 Elements (e. f, g, t, i,j)

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A manufacturer knows that their items have a normally distributed lifespan, with a mean of 7 years, and standard deviation of 1.6 years.
$3.00$2.00Question: A manufacturer knows that their items have a normally distributed lifespan, with a mean of 7 years, and standard deviation of 1.6 years.
If you randomly purchase one item, what is the probability it will last longer than 11 years?