Joe Greene, a new manager at Pilgrim Bank wants to better understand profitability data for bank’s customers. Joe is able to obtain a random sample of 31,634 customers on the following variables – Profitability (in $, for the most recent completed year, i.e. 2006), whether or not the customer uses the online banking channel, customer tenure, age and income where available, as well as the customer’s residential area. Descriptive statistics for Profits indicates that the average profit per customer is $111.50 with a standard deviation of $272.84.

a. Is Joe justified in assuming that this is a “large” sample? (see slide 7-14) YES, BECAUSE 31,634 IS A LOT MORE THAN 30 OBVERSATIONS. GENERALLY, THE LARGER THE SAMPLE, THE MORE RELIABLE ARE THE ESTIMATES. THE KEY IS TO HAVE A RANDOMLY SELECTED SAMPLE TO REDUCE THE RISK OF BIASED ESTIMATES

b. Joe has been informed that the bank serves approximately 5 million customers nationwide – should he worry about using finite population correction factor (slide 7-9). FINITE POPULATION CORRECTION (FPC) IS NOT NECESSARY, SINCE THE POPULATION OF APPROXIMATELY 5 MILLION IS QUITE LARGE. FPC IS ONLY RECOMMENDED FOR SMALL POPULATIONS.

c. Joe wants to estimate average profit for the entire population based on his sample. He knows that the “point estimate” for average profit would be $111.50, but, he will need to calculate the margin of error. The first step for this is to calculate the standard error (see slide 7-6); provide the value below. 272.84 / SQRT(31,634) = $1.53

d. The second step in calculating the margin or error (often simply called error) is to multiply the standard error by 1.96; provide the value below. 1.96*$1.53=$3. THUS THE MARGIN OF ERROR FOR OUR ESTIMATE OF AVERAGE PROFIT PER CUSTOMER, FOR THE ENTIRE CUSTOMER BASE WILL BE $3

e. Joe can combine responses from c and d to report the estimated average profit customer for all the bank’s customers as...

...2008. NOT FOR COMMERCIAL DISTRIBUTION
3
Simple Random Sampling
3.1 INTRODUCTION
Everyone mentions simple random sampling, but few use this method for population-based surveys. Rapid surveys are no exception, since they too use a more complex sampling scheme. So why should we be concerned with simple random sampling? The main reason is to learn the theory of sampling. Simple random sampling is the basic...

...CHAPTER 12
SAMPLING MECHANICS
Sampling is an activity that involves the selection of individual people, data or things, from a target population/universe.
A population, or universe, is the entire set people data or things that is the subject of exploration.
A census involves obtaining information, not from a sample, but rather from the entire population or universe.
A sample (as opposed sampling) is a subset of the population/universe....

...
Sampling and Data collecting Plan
October 9, 2014
University of Phoenix
QNT/561
Team D has chosen to look into whether or not should Pear Inc. should start putting their resources into either Laptops or tablet electronic devices. Putting resources into a venture that may or not pan out could be detrimental to that same company. As an example; Kodak and their choice not to expand into digital, something they created, and stay the course with their...

...
Sampling and Data Collection Plan
Name
QNT/561
October 27, 2014
Instructor
Introduction
Royal Blue Airlines is a medium sized airline company offering flights throughout the United States, Mexico, Caribbean Islands, and Latin America. The company operates a fleet of Boeing 737 aircrafts and is in the process of replacing older ones with newer, state-of-the-art planes. These new planes are very expensive, so management wants to maximize passenger count. A...

...destruction who refuses to accompany him.
Pliable- A neighbor if Christians who accompanies him for a while. After falling though the slough of Despond , Pliable is discouraging and returns home, only to be mocked by the townsfolk.
Help- Fellow pilgrim who helps pull Christian from the Slough of Despond.
Worldly Wiseman- A reasonable and practical man whom Christian encounters early in his journey Worldly Wiseman tries unsuccessfully to urge Christian to give up his religious...

...CHAPTER 7—SAMPLING AND SAMPLING DISTRIBUTIONS
MULTIPLE CHOICE
1. From a group of 12 students, we want to select a random sample of 4 students to serve on a university committee. How many different random samples of 4 students can be selected?
a.|48|
b.|20,736|
c.|16|
d.|495|
ANS: D
2. Parameters are
a.|numerical characteristics of a sample|
b.|numerical characteristics of a population|
c.|the averages taken from a sample|
d.|numerical...

...SAMPLINGSAMPLING
SAMPLING DISTRIBUTION
(THEORETICAL)
SAMPLING TECHNIQUES (APPLIED)
8/13/2014
QM_Session 14 15
SAMPLING TERMS
An unit/element is the entity on which data are collected.
A population is a collection of all the units/elements of
interest.
A sample is a subset of the population.
The sampled population is the population from
which the sample is drawn.
A frame is a list of the elements/units that the...

...Population and Sampling
MTH/231
August 29, 2012
Importance of Population and Sampling
History from Political Arithmetic to Statistics
The history timeline show evidence of statistical data as early as Ancient Greece time but records show statistics in late 16th century, when it was introduced by, John Graunt, William Petty, and Pascal and later in 17th century by Gottfried Achenwall. It was an exciting time when success and discoveries raised the...

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