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Distribution of Sample Mean: Breaking strength of steel cable

The breaking strength of a certain brand of steel cable is normally distributed, with a mean of µ = 2500 pounds, and a standard deviation of Ï? = 250 pounds. If a construction company buys 25 cables, what is the probability that they will have a mean breaking strength of at least 2400 pounds? Express your answer as a d

Infomercials Products

Infomercials often peddle products under the guise of "studies show". While some of the products are surprisingly good (e.g., FoodSaver, Foreman Grill, Ronco Rotisserie), many of the products are not. a. Why should you be initially suspicious of any products advertised on these shows, despite the "existence" of data? b. What

Population Parameter and Sample Estimate

You have been told that for university classes, students are supposed to spend two hours working outside of class for each hour in class. You are curious to know the average amount of time students at your school spend working outside of class for each hour in class. You contact 100 students at your school and ask them, 'How ma

Random Sampling for proportion of population

5. The manager of University Credit Union (UCU) is concerned about checking account transaction discrepancies. Customers are bringing transaction errors to the attention of the bankâ??s staff several months after they occur. The manager would like to know what proportion of his customers balance their checki

Statistics: Identification of Sampling Method and Analysis

1. Five early adolescents in each program participated in the study. The young people ranged in age from 11 to 13 years and all were racial minorities. The three boys in the Manhattan neighborhood were of Hispanic/Latino origin and the two girls were African American. Conversely, the four boys in the Bronx neighborhood were Afr

Statistics: Sampling and Sampling Distributions

1.) Suppose a simple random sample of size 50 from a population with a mean of 10. Find the value of the standard error of the mean in each of the following cases (use the finite population correction factor if appropriate.) a.) the population size is infinite b.) the population size is N=50,000 c.) the population size is N

Sampling from a population.

The file HP.xls contains the ages of 48 moviegoers to a recent showing of a Harry Potter movie.The following two methods illustrate in different ways how you might select a random sample of eight moviegoers' ages. In each case use the initial order of the files ages as the starting point, so that the first person in the list is

Sample size for mean and Proportion

A consumer agency has retained an independent testing firm to examine a television manufacturer's claim that its 25-inch console model consumes just 110 watts of electricity. Based on a preliminary study, the population standard deviation has been estimated as 11.2 watts for these sets. In undertaking a larger

8.25 Error of the Sample Proportion for female purchasing managers

SEE ATTACHED FILE - Error of the Sample Proportion It has been reported that 42.6% of U.S. workers employed as purchasing managers are females. In a simple random sample of U.S. purchasing managers, 70 out of the 200 are females. Given this information: a. What is the population proportion, π? b. What is the sample

Independent variable for ballet training of baseball team

A coach in a large high school thinks that ballet training will improve the batting performance of his baseball team. He decides to have a randomly selected half of the team take six weeks of ballet training before the baseball season begins, while the other half does not take such training. He will then compare the season bat

Statistics and Sampling: Example Problem

Assume we have three different samples each comprised of 20 different jurisdications. Our objective is to compare the seriousness of juvenile substance abuse across all the samples. Sample 1 has en average of 1862 arrests of youth substance abuse; Sample 2 has an average of 3965 and Sample 3 has an average of 2398 arrests. W

T Tests for Independent and Related Samples: 6 problems

See attached file for clarity. t Tests for Independent and Related Samples Problem Set 2: Chapter 10 & 11: problems: Chapter 10: 2. Describe what is measured by the estimated standard error in the bottom of the independent -measures t-statistic. 18. In 1974, Lotus and Palmer conducted a classic study demonstrat

Analyzing data involving sex distribution, age, ethnicity

(1) Determine 10 variables of interest and determine the appropriate scale of measurement for each variable using the excel sheet attached. (2) Choose and compute the appropriate descriptive statistics to describe characteristics of the sample under study (such as sex distribution, age, and ethnicity) and the anxiety reported

Sampling distribution of sample mean..

In the article "Job Mobility and Wage Growth" (Monthly Labor Review, Vol. 128, No. 2, pp 33-39), A. Light examines data on employment and answers questions regarding why workers separate from their employers. According to the article, the standard deviation of the lengths of time that women with one job are employed during the

distribution of sample means, deviation, sample size, random selection

2. Describe the distribution of sample means (shape, expected value, standard error) for samples n= 36 selected from a population with a mean of µ =100 and a standard deviation of Ï? = 12. 6. For a population with a mean of µ =50 and a standard deviation of Ï? = 10, how large a sample mean (M) and the population mean for

6-7: Sample size for candidate preference with 90% confidence level

A pollster for a congressional candidate would like to determine the proportion of the voting population who prefers this candidate at this time over the competition. He would like to estimate with .05 of the true proportion with a confidence level of 90%. What is the sample size needed? a) 171 b) 271 c) 298 (See the atta

Estimate the mean total cholesterol levels of children 2 - 6 years of age

A study is run to estimate the mean total cholesterol level in children 2- 6 years of age. A sample of 9 participants is selected and their total cholesterol levels are measures as follows: 185,180,225,240,194,147,196,175 and 223. a. Compute the sample mean b. Compute the sample standard deviation c. Compute the median d.

Nonprobability Sample Data

Your task is to interview a representative sample of attendees for the large concert venue where you work. The new season includes 200 live concerts featuring all types of musicians and musical groups. Since neither the number of attendees nor their descriptive characteristics are known in advance, you decide on a nonprobability

Statistics sampling methods: Independent, dependent, and matched pair samples

1. Determine whether the sampling method is independent or dependent for the following example. A researcher wants to know whether the newly issued "state" quarters have a mean weight that is different from "traditional" quarters. He randomly selects 18 "state" quarters and 16 "traditional" quarters. Their weights are compared.

Sampling Distribution for Process Repeated

Consider the process of repeatedly taking SRSs of size n from a heavily left--‐skewed population distribution with mean μ and standard deviation and calculating the sample mean x (a) What is the mean of the sampling distribution of x (b) What is the standard deviation of the sampling distribution of

Independent or Dependent Samples

1. Classify as independent or dependent samples: White blood cell counts for a group of volunteers before being innoculated, and white blood cell counts for a second group of volunteers after being innoculated. 2. Classify as independent or dependent samples: White blood cell counts for a group of volunteers before being inno

Statistics: Sample mean of breaking strength for trash bag manufacturer

Recall that the trash bag manufacturer has concluded that its new 30 gallon bag will be the strongest such bag on the market if its mean breaking strength is at least 50 pounds. In order to provide statistical evidence that the mean breaking strength of the new bag is at least 50 pounds, the manufacturer randomly selects a sampl

Statistics - Simple Random Sampling & Cluster Sampling

Compare the differences of simple random sampling and cluster sampling using specific examples, and show the advantages and disadvantages of each method. What are the advantages and disadvantages of systemic random sampling and stratified random sampling?

Occupational Group for Alcoholism

A state magazine once published a story saying that farmers lead other groups in the consumption of alcohol. As evidence, it pointed to the fact that a rehabilitation center located in the rural part of the state treated more farmers than any other occupational group for alcoholism. Do you agree? Why or why not? Justify your

Identifying Sample and Populations

Identify the sample and population 1. a. A group of 50,000 randomly selected college students were surveyed about whether they have a TV in their dorm room. Only 75% said yes to the question. i. Sample - ii. Population - b. An employee at the local ice cream emporium asks 3 customers if they liked cookie dough ice