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# Sampling

### Distribution of proportion

Central limit theorem: Sample proportion A minority representation group accuses a major bank of racial discrimination in its recent hires for financial analysts. Exactly 10% of all applications were from minority members, and exactly 8% of the 900 open positions were filled by members of the minority. 1. Find the mean of

### Differences Between Independent and Dependent Samples

Explain the difference between independent samples and dependent samples. Classify the following as independent or dependent samples: Weights of identical twins The effectiveness of two different brands of ibuprofen Effect of a new training program on time taken to complete a task, measured by a "before" and "after" t

### Sampling Distributions

Strater, Inc. makes particleboard for the building industry. Particleboard is made by mixing wood chips and resins together, forming the mix into 4 foot by 8 foot sheets, and pressing the sheets under extreme heat and pressure to form a sheet that is used as a substitute for plywood. The strength of the particleboard is tied to

### Sample Size for the Estimation of Mean for Elephants

In a study of elephants a researcher wishes to determine the average weight of a certain subspecies of elephants. From previous studies, the standard deviation of the weights of elephants in this subspecies is known to be 1500 pounds. How many elephants does the researcher need to weigh so that he can be 80% confident that the

### Sampling Distribution of Sample Mean - Standard Deviation

The mean weight of loads of coal placed in train cars by a loading machine is 43.0 tons with a standard deviation of 8.0 tons. Assuming that the weight of loads placed in the train cars by this loader are normally distributed, if a random sample of 9 loads is chosen for a weight check, find the probability that the mean weight o

### Homogeneous Grouping Samples

What type of sample methods are these? a. Certain kinds of either typical or atypical cases are deliberately chosen. b. large proportion of very small homogeneous groupings than larger ones.

### Sampling distribution

Suppose the annual consumption of chicken mean is 20.84 pounds per person, and that the standard deviation for the consumption of chicken per person is 9.193 pounds. The mean weight of chicken consumed for a sample of 200 randomly selected people is one value of many that form the sampling distribution of sample means. Descri

### Discuss statistics concepts

Can you help me explain these: Systematic sample Stratified Sample Weighted mean Standard deviation Mutually exclusive events Independent events, and Expected value Please include example in your response to enhance my understanding. Thanks

### Statistics: Samples vs. Populations

In your opinion can you explain the difference between a population and sample and why do we normally study a sample than a population? Provide a brief discussion of the following. Include examples in you response to enhance my understanding: systematic sample; stratified sample; weighted mean; standard deviation; mutually ex

### Calculating sample variances and poolded variance

One sample has SS = 35 and a second sample has SS = 45. a. Assuming that n = 6 for both samples, calculate each of the sample variances, then calculate the pooled variance. Because the samples are the same size, you should find that the pooled variance is exactly halfway between the two sample variances. b. Now assume t

### Techniques for gathering data: Sampling, experiment, simulation, census

What technique for gathering data (sampling, experiment, simulation or census) do you think was used in each of the following studies? a) A computer program was used to model global weather patterns and to produce long-range weather forecasts for a rural agricultural region. b) A random sample of 1,000 residents of a major

### Survey methods for marketing.

A food chain company based in Florida wants to expand in Georgia. You, as a part of the marketing team, are required to find the popularity of fast food among the younger generation. What method is best suited for such a survey? Draw the sample using the random number table and bring out the rationale of the procedure.

### The answer to Point estimate

During the month of July, an auto manufactures gives its production employees a vacation period so it can tool up for the new model run. In surveying a simple random sample of 200 production workers, the personnel director finds that 38% of them plan to vacation out of state for at least one week during this period. Is this a p

### Distribution of Sample Mean

Please see the attached file. Three shafts are made and assembled in a linkage. The length of each shaft, in centimeters, is distributed as follows: Shaft 1: l_1 ~ N(75,0.09) Shaft 2: l_2 ~ N(60,0.16) Shaft 3: l_3 ~ N(25,0.25) The length of the linkage is calculated by l = l_1 + l_2 + l_3. Assume the shafts' length ar

### What is the minimum sample size needed in order for the consumer group to be 99% confident that its estimate is within 175 miles per month of µ ?

A consumer advocacy group is doing a large study on car rental practices. Among other things, the consumer group would like to estimate the mean monthly mileage,µ , of cars rented in the U.S. over the past year. The consumer group plans to choose a random sample of monthly U.S. rental car mileages and then estimate µ using the

### Sample spaces and sets, union and intersections

Please see the attached file. ------ In control replication, cells are replicated over a period of two days. Not until mitosis is completed, can freshly-synthesized DNA be replicated again. Two control mechanisms have been identified - one positive and one negative. Suppose that a replication is observed in three cells.

### Statistics - Sample Distribution

Here are the number of sales per day that were made by Kim Ryan, a cautious telemarketer who worked 4 days before being fired: 1, 11, 9, and 3. Assume that samples of size 2 are randomly selected with replacement from this population of 4 values. Find the mean of the sampling distribution.

### Automotive Suppliers: Quality Control

An automotive industry supplier produces pistons for several models of automobiles. Twenty samples, each consisting of 200 pistons, were selected when the process was known to be operating correctly. The numbers of defective pistons found in the samples follow. SEE ATTACHMENT FOR TABLE a.What is an estimate of the prop

### Complete Solution

1. The objective of statistics is best described as: a) To make inferences about a sample based on information we get from a population b) To use population mean, m as an estimate of the sample mean, c) To make inferences about a population based on information we get from a sample taken from the population d) To make inf

### Sampling distributions

Suppose the population mean is 50.6 pounds with a population standard deviation of 1.62 pounds. Suppose we take thousands of samples with a sample size of 40. What will the mean of these sample means be? What will the standard deviation of the sample means be?

### Sample Size - A New York Times article about poll results states, "In theory, in 19 cases out of 20, the results from such a poll should differ by no more than one percentage point in either direction from what would have been obtained by interviewing all voters in the United States." Find the sample size suggested by this statement.

A New York Times article about poll results states, "In theory, in 19 cases out of 20, the results from such a poll should differ by no more than one percentage point in either direction from what would have been obtained by interviewing all voters in the United States." Find the sample size suggested by this statement.

### Importance of Sampling

In research (quantitative or qualitative) you will almost always find it is important to sample. Please explain why sampling is important and its implications in the knowable/unknowable debate. Consider in you response how the concepts of a population (and its associated parameters) and the sample (and its associated estimat

### Bootstrapping versus Double Sampling

What is the difference between resampling (bootstrapping) and double sampling in research? Is there any difference or is the same? Please explain your response?

### Sampling Methods: Random and Volunteer Samples

Some television stations attempt to gauge public opinions by posing a question on the air and asking viewers to call to give their opinions. Suppose that a particular television station asks viewers whether they support or oppose a proposed federal gun control law. Viewers are to call one of two 800 numbers to register support o

### Statistics: Sampling Distribution and Estimation

8.46 A random sample of 10 miniature Tootsie Rolls was taken from a bag. Each piece was weighed on a very accurate scale. The results in grams were 3.087 3.131 3.241 3.241 3.270 3.353 3.400 3.411 3.437 3.477 (a) Construct a 90 percent confidence interval for the true mean weight. (b) What sample size would be necessary to

### The following data give the weekly amounts spent on groceries for a sample of households.

Please help with solving these problems - see the attached file.

### MCQs in Statistics - Answers and explanations are both required.

There are 10 multiple choice questions but i need all work shown and explanation for answers: 1. The Central Limit Theorem says that , if n exceeds 30, a histogram of the sample will have a bell-shape, even if the population isn't normal. A) True B) False 2. In a sample size calculation for a mean, if the

### Random Sampling

You have 400 employees, numbered 1-400. you want to interview 15. Describe how to randomly select the employees. Please solve on excel spreadsheet.

### Census, experiment, simulation, and sampling

I have to state if the answer is experiment, census, simulation, or sampling. I have my answers but I am not certain of one of them. 1)An Analysis of a sample of 20,000 people from LA had suggested that elderly and homeless sue for malpracticeat 1/4th the rate of wealthier patients. 2)The effects of wind on the takeoff an

### Types of Sampling

Categorize as simple, random, sample, stratified/systematic sample, cluster/convenience sample. 1) List discharged hotel customers, divide them day their length of stay, and draw simple random samples from each group. 2) List discharged hotel customers, number the customers and use random number table to obtain sample.