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# Descriptive Statistics

### Interval Estimates vs. Point Estimates & Practical Population Mean Data

Question 1: Why is an interval estimate for the population preferred to a point estimate? Question 2: In real business practices, is information about the population mean available? Discuss

### Discuss Validity of Central Limit Theorem

What is the Central Limit Theorem? How large should the sample size be if the underlying distribution of the population values are: a. Normally distributed (discuss). b. Non-normally distributed. (discuss) 2. What is the difference, if any, between the standard deviation of the sample and the standard error of the mean

### Statistics: measures of central tendency

Table 1 An insurance company evaluates many numerical variables about a person before deciding on an appropriate rate for automobile insurance. A representative from a local insurance agency selected a random sample of insured drivers and recorded, X, the number of claims each made in the last 3 years with the following results

### statistical observation

A. Select a topic of interest - preferably College related such the height of students or the number of hours they take to prepare for classes. B. Choose 2 variables to observe: 1) Female and 2) Male C. Collect 20 data points on each variable 1. Perhaps, you may design a questionnaire to collect you data 2. The design of you

### Descriptive and Inferential Statistics Identification

Identifying the discriptive and inferential statistics in the research article (article link below): http://ptjournal.apta.org/content/89/12/1275.full.pdf+html

### MANOVA in Drug Selection

In this exercise, you are playing the role of a researcher that is testing new medication designed to improve cholesterol levels. When examining cholesterol in clinical settings, we look at two numbers: low-density lipoprotein (LDL) and high-density lipoprotein (HDL). You may have heard these called "good" (HDL) and "bad" (LDL)

### Dependent Sample T-test

In this activity, we are interested in finding out whether participation in a creative writing course results in increased scores of a creativity assessment. For this part of the activity, you will be using the data file "Activity 4a.sav". In this file, "Participant" is the numeric student identifier, "CreativityPre" contains cr

### Defining descriptive statistics

Please provide a brief definition of descriptive statistics and their usage in everyday life.

### Correlation Coefficient for Absenteeism and Age

A personnel manager for a large corporation feels that there may be a relationship between absenteeism and age and would like to use the age of a worker to develop a model to predict the number of days absent during a calendar year. A random sample of 10 workers was selected with the results presented below: Age Da

### Finding the Confidence Interval at 95% Confidence

A sample of 75 information system managers had an average hourly income of \$40.75 with a standard deviation of \$7.00. What is the 95% confidence interval for the average hourly wage of all information system managers?

### Computing the slope of regression line for given data

The following information regarding a dependent variable Y and an independent variable X is provided S = SUM (SX means Sum of x values) SX = 90 S (Y - nar008-1.jpg)(X - nar008-2.jpg) = -156 SY = 340 S (X - nar008-3.jpg)2 = 234 n = 4 S (Y - nar008-4.jpg)2 = 1974 SSR = 104 The slope of the regression equation is

### Application of Central Limit Theorem

Random samples of size 81 are taken from an infinite population whose mean and standard deviation are 200 and 18, respectively. The distribution of the population is unknown. The mean and the standard error of the mean are?

### Finding the Slope of Regression Line

The following information regarding a dependent variable Y and an independent variable X is provided S = SUM (SX means Sum of x values) SX = 90 S (Y - nar008-1.jpg)(X - nar008-2.jpg) = -156 SY = 340 S (X - nar008-3.jpg)2 = 234 n = 4 S (Y - nar008-4.jpg)2 = 1974 SSR = 104 Find the slope of the regression equati

### Calculating sample confidence interval for a population mean

Please see attachment for the data to be used when answering these questions. a. Develop a 95% confidence interval for the mean number of miles driven until transmission failure for the population of automobiles with transmission failure. Provide a managerial interpretation of the interval estimate. b. Discuss the implicat

### Implication of Negative Correlation

Assuming a linear relationship between X and Y, if the coefficient of correlation (r) equals - 0.30, a. there is no correlation b. the slope (b1) is negative C. Variable X is larger than variable Y D. The variance of x is negative

### Determining the Required Sample Size

An economist is interested in studying the incomes of consumers in a particular region. The population standard deviation is known to be \$1,000. A random sample of 50 individuals resulted in an average income of \$15,000. What sample size would the economist need to use for a 95% confidence interval if the width of the interval s

### Library of Congress

The head librarian at the Library of Congress has asked her assistant for an interval estimate of the mean number of books checked out each day. The assistant provides the following interval estimate: from 740 to 920 books per day. If the head librarian knows that the population standard deviation is 150 books checked out per da

### Make use of dummy variable in the regression analysis

First, explain in your own words (no direct quotes, please) what a dummy variable is and its purpose in regression analysis. Secondly, provide an example of where you might use a dummy variable from your own professional experience. Thirdly, briefly describe how you would implement a dummy variable in a data table you intend to

### Relationship Between Sampling Mean and Population Mean

Drug manufacturer knows that for a certain antibiotics, the average number of doses ordered for a patient is 20. Steve Simmons, a salesman for the company, after looking at 1 day's prescription orders for the drug in his territory, announced that the sample mean for this drug should be lower. He said, "For any sample, the mean s

### Introductory Statistics

Let x be a random variable representing dividend yield of Australian bank stocks. We may assume that x has a normal distribution with f\$sigma f\$ = 2.8%. A random sample of 16 Australian bank stocks has a sample mean dividend yield of 8.91%. For the entire Australian stock market, the mean dividend yield is f\$mu f\$ = 6.4%. If

### Statistics 2

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

### Differences in Descriptive and Inferential Statistics

Examine the differences between descriptive and inferential statistics. Address the following items: Describe the functions of statistics. Define descriptive and inferential statistics. Provide at least one example of the relationship between descriptive and inferential statistics.

### The solution gives detailed steps on determining slope and intercept on the regression line using excel.

A company has observed that there is a linear relationship between indirect labor expense (ILE) , in dollars, and direct labor hours (DLH). Data for direct labor hours and indirect labor expense for 18 months are given in the file ILE_and_DLH.xlsx Treating ILE as the response variable, use regression to fit a straight line t

### Norms and Standardized Samples

Please help answer the following question. Provide at least 400 words in the solution. What is the relationship between a standardization sample and test norms?

### The solution gives detailed steps on calculating t-statistic and p-value using t test for population mean when standard deviation is unknown.

Consider the e-billing case. The mean and the standard deviation of the sample of n = 65 payment times are = 18.7598 and s = 3.9494. Test H0: μ = 19.1 versus Ha: μ < 19.1 by setting α equal to .01 and using a critical value rule and assume normality of the population. (Round your "t" and "t0.01" answers to 3 decimal places

### Choosing a method to measure central tendency

All of the full questions (including methods to measure central tendency) are in the attached document.

### Correlation Analysis for Birth Rate Variation

1. Data are gathered on 40 countries to study variations in birth rate. Consider an equation derived in the study: where: Y = birth rate per 1,000 population X = per capita income a. Identify the following: the independent and dependent variables the regression coefficient

### Patterns in linear regression models

What pattern would you need to decide that the linear regression model is appropriate? What would you do if you found a curvilinear pattern or no pattern at all? Discuss how to calculate the best-fitting line in a scatter plot (regression analysis).

### Constructing Graphic Representation of Random Samples

Question 1 To compare commuting times in various locations, independent random samples were obtained from the six cities presented in the "Longest Commute to Work" graphic on page 255 in your textbook. The samples were from workers who commute to work during the 8:00 a.m. rush hour. One-way Travel to Work in Minutes Atlanta Bo

### Determining the Number of Trial Runs of a Chemical Process

A production supervisor at a major chemical company wishes to determine whether a new catalyst, catalyst XA-100, increases the mean hourly yield of a chemical process beyond the current mean hourly yield, which is known to be roughly equal to, but no more than, 750 pounds per hour. To test the new catalyst, five trial runs using