You decide to measure the time between equipment malfunctions over a one-year period. Over that time you measured 40 electronic products. You made 850 observations with a mean time between equipment failures of 550.35 hours, and a sample standard deviation of 207 hours. Your company supplies the electronic product to anoth
A US Navy recruiting center knows from past experience that the height of its recruits are normally distributed with mean 68 inches. The recruiting center wants to test the claim that the average height of this year's recruits is greater than 68 inches. To do this, recruiting personnel take a random sample of 64 recruits from th
Margin of error - 1. Under the case that population standard deviation delta is known and sample size n > 30. Show the margin of error for a 95% confidence interval (CI) for population mean µ as follows ...
1. Under the case that population standard deviation delta is known and sample size n > 30. Show the margin of error for a 95% confidence interval (CI) for population mean µ as follows c = 1:96 (delta/sqrt n) (c= 1.96 x populations standard mean/square root of sample size n) What will happen about the margin of erro
Sample of 20 pages was taken out replacement from the 1,591 page directory. On each page the main areas devoted to display ads was measured. The data is square millimeters are shown 0 260 356 403 536 0 268 369 428 536 268 396 469 536 162 238 403 536 536 130 a) Construct a 95 per cent confidence intervals for the true mea
Assume the population standard deviation is 3.8 thousand dollars. 4.4 6.5 4.2 8.9 8.7 8.1 6.1 6.0 2.6 2.9 8.1 -1.9 11.9 8.2 6.4 4.7 5.5 4.8 3.0 4.3 -6.0 1.5 2.9 4.8 -1.7 9.4 5.5 5.8 4.7 6.2 15.0 4.1 3.7 5.1 4.2 a) Verify that for the data, x(x bar)=5.1, find 8
25 Multiple choice questions on Standard deviation, Hypothesis testing and other statistics concepts
Please see the attached file. 1 If you were constructing a 99% confidence interval of the population mean based on a sample of n = 25 where the standard deviation of the sample s = 0.05, the critical value of t will be: a.) 2.7969. b.) 2.7874. c.) 2.4922. d.) 2.4851. 2 The diameter of Ping-Pong balls manufactured a
Confidence Interval and Hypothesis Testing - 2. A sample of 81 observations is taken from a normal population. The sample mean is 40, and the sample standard deviation of 5. Determine the 95 percent confidence interval for the population mean. 3. Merrill Lynch Securities and Health Care Retirement, Inc, are two large employers in down ... [See the attached Quesstions File]
2. A sample of 81 observations is taken from a normal population. The sample mean is 40, and the sample standard deviation of 5. Determine the 95 percent confidence interval for the population mean. 3. Merrill Lynch Securities and Health Care Retirement, Inc, are two large employers in down Toledo, OH. They are considering joi
Directions: 1) Calculate a point estimate and a 95% confidence interval of the mean. Assuming your data set is normally distributed, determine an appropriate sample size if the maximum allowable error is three units for the attached data set. (Please note: the three units are measure in the unit of measurement of the attache
In a new poll where people were asked on whether or not they will vote for a presidential candidate: 1600 people were picked randomly from a population that amounts to about 80 million eligible voters. The results were as follow: N Obama Mccain Undecided 1600 900 600 100 Estim
2. The following table classifies 800 telephone calls by type (local or long distance) and by length: (6 points) a. What is the probability that a call sampled at random out of this population is local and 1 -5 minutes long? b. What is the probability that a call sampled at random is long distance? c. What is the probability that a call is not 5+ minutes given that is a long distance call?
Please answer the following questions in Microsoft Excel. There are six questions total. Work on how to do it should be shown. 2. The following table classifies 800 telephone calls by type (local or long distance) and by length: (6 points) a. What is the probability that a call sampled at random out of this population is l
How do you find the Confidence Interval for a particular Confidence Level, such as 95%, for a sample of more than 30 people? Show the exact formulas that you use in this situation to calculate the sample standard deviation and standard error?
Joel Friedlander is a broker on the New York Stock exchange who is curious about the amount of time between the placement and the execution of a market order. Joel sampled 25 orders and found that the mean time to execution was 24.3 minutes with a standard deviation of 3.2 minutes. Help Joel by constructing a 90 percent confid
Suppose a sample of 50 is taken from a population with a standard deviation of 27 and that the sample mean is 86. Establish a 95.5% interval estimate for the population mean, Suppose, instead, that the sample size was 5000. Establish a 95.5% interval estimate for the population mean. Why might you prefer one estimate over th
A researcher investigating sex role stereotypes and occupational aspirations drew a random sample of 125 female university students. She discovered that 55 plan to go on to graduate school. Construct the 90% confidence interval for the true proportion of women seeking higher education. Show your work.
4) A building developer has the opportunity to purchase several acres of land that is divided up into several lots for building single-family homes... 6) One of the problems encountered by corporations in America is finding an adequate number of employees who want to move into management. Recent surveys of workers in America...
4) A building developer has the opportunity to purchase several acres of land that is divided up into several lots for building single-family homes. It is known that the average sale price of all of the lots is $80,000 and the standard deviation of the sale price is $12,000. What can you say about the percentage of lots that ha
5. State the main points of the Central Limit Theorem for a mean. 6. Why is population shape of concern when estimating a mean? What does sample size have to do with it?" (Doane and Seward, p. 338) Exercise 8.46 A random sample of 10 miniature Tootsie Rolls was taken from a bag. Each piece was weighed on a very accur
Please find the problems attached.
Explain why a confidence interval for a predictor coefficient is equivalent to a 2-tailed test of significance?
For a random sample of 10 fifth generation iPod music players, the mean battery life was 9.47 hours with a standard deviation of 2.14 hours. a. Construct a 95% confidence interval for the mean number of hours the batteries will last on these players. b. Suppose you wanted more accuracy, what could you do to increase the
A survey conducted during May 20 - 22, 2005, asked 1006 Americans, "During the past year, about how many book, either hardcover or paperback, did you read either all or part of the way through?" Results of the survey indicated that the mean of the sample was 13.4 books with a standard deviation of 16.6 books. Construct a 99% c
Please see attachment.
1. The following sample of 16 measurements was selected from a population that is approximately normally distributed: 91 80 99 110 95 106 78 121 106 10 97 82 100 83 115 104. Construct a 95% confidence interval for the population mean. 2. In a survey of 1000 persons, 290 responded that they approve of the president's job perfo
1) The diameter of Ping- Pong balls manufactured at a large factory is expected to be approximately normally distributed with a mean of 1.30 inches and a standard deviation of 0.40 inch. What is the probability that a randomly selected Ping-Pong ball will have a diameter between 1.31 and 1.33 inches? A) 0.0987 (B) 0.1747 (C) 0.
Please see the attached file. 1. What is the appropriate critical value for each of the following confidence levels and sample sizes? (Remember that in regard to confidence level this implies two-tails) (a) Critical z-value for an 85% confidence level for sample of size n = 36: (b) Critical t-value for
11 Multiple choice questions on Normal Distribution, t distribution, confidence interval, sampling distribution of the mean, standard error of the mean.
1) If you were constructing a 99% confidence interval of the population mean based on a sample of n=25 where the standard deviation of sample s = 0.50, the critical t will be: A) 2.7969 (B) 2.7874 (C) 2.4922 (D) 2.4851 2) A statistician wishes to estimate the average total compensation of CEOs in the service industry. Data w
Please provide the evidence of your work. Thank you.
Assume that in a hypothesis test with null hypothesis = 13.0 at 0.05, that a value of 11.0 for the sample mean results in the null hypothesis not being rejected. That corresponds to a confidence interval result of A. The 95% confidence interval for the mean does not contain the value 13.0 B. The 95% confidence interval for
Use the traditional method to test the given hypothesis. Assume that the population is normally distributed and that the sample has been randomly selected. 10) In one town, monthly incomes for men with college degrees are found to have a standard deviation of $650. Use a 0.01 significance level to test the claim that for men wi
Use the traditional method to test the given hypothesis. Assume that the samples are independent and that they have been randomly selected 11) In a random sample of 500 people aged 20 24, 22% were smokers. In a random sample of 450 people aged 25 29, 14% were smokers. Test the claim that the proportion of smokers inthe two age
1. Suppose a sample of n = 50 items is drawn from a population of manufactured products and the weight, X, of each item is recorded. Prior experience has shown that the weight has a probability distribution with m= 6 ounces and standard deviation= 2.5 ounces. Which of the following is true about the sampling distribution of