Collecting Data
How Data is Collected
The following are a few frequently used methods for how data is collected:
Personal Interview
People usually respond when asked by a person but their answers
may be influenced by the interviewer.
Telephone Interview
C
An Overview of Statistics
We begin this class by following up on the 'What is Statistics' video and explaining why we study
statistics and what statisticians do. When discussing the subject of sample data collection, we will
draw a distinction between an
Conditions to Check Before One Can Use the tInterval
Unit Summary
Conditions When One Can Use t-Procedure for Population Mean
Using Normal Probability Plot to Check Normality
What to Do If One Cannot Use the t-Procedure
Conditions When One Can Use t-Proce
Sample Size Computation for the Population Mean
Unit Summary
Margin of Error: Half Width of the Interval
Sample Size Computation for Population Mean
Margin of Error: Half Width of the Interval
A 100(1)100(1) CI for is:
xt/2sn, x+t/2snxt/2sn, x+t/2sn
where
Sampling Distribution of the Sample Mean
General Objective: In inferential statistics, we want to use characteristics of the sample (i.e.
a statistic) to estimate the characteristics of the population (i.e. a parameter). What happens when
we take a sample
Inference for the Population Mean
Inferences for the Population Mean When the Population Standard Deviation is Unknown
t-Distribution
General Comments About Confidence Intervals
Inferences for the Population Mean When the Population Standard
Deviation is
Inference for the Binomial Parameter: Population
Proportion
Unit Summary
Introduction to Inferences
Estimation
Properties of 'Good' Estimators
General Format and Interpretation of a Confidence Interval
Inferences on the Binomial Parameter p
Confidence Int
Practice Problems with Solutions
1. The company JCrew advertises that 95% of its online orders ship within two working days. You
select a random sample of 200 of the 10,000 orders received over the past month to audit. The audit
reveals that 180 of these
Sampling Distribution of the Sample Proportion
What if we do not have continuous data?
In the baseball example we used at the end of the prior lesson on sampling distribution of sample
mean, say we coded 0 for salaries not above the mean and 1 for salarie
MAT 230 Module Six Homework
General:
Before beginning this homework, be sure to read the textbook sections and
the material in Module Six.
Type your solutions into this document and be sure to show all steps for
arriving at your solution. Just giving a
MAT 230 Module 7 Homework
General:
Before beginning this homework, be sure to read the textbook sections and
the material in Learning Module 7.
Type your solutions into this document and be sure to show all steps for
arriving at your solution. Just givi
MAT 230 Module Three Homework
General:
Before beginning this homework, be sure to read the textbook sections and
the material in Module Three.
Type your solutions into this document and be sure to show all steps for
arriving at your solution. Just givin
MAT 230 Module Four Homework
General:
Before beginning this homework, be sure to read the textbook sections and
the material in Module Four.
Type your solutions into this document and be sure to show all steps for
arriving at your solution. Just giving
MAT 230 Module Five Homework
General:
Before beginning this homework, be sure to read the textbook sections and
the material in Module Five.
Type your solutions into this document and be sure to show all steps for
arriving at your solution. Just giving
MAT 230 Exam Two
General:
Before beginning this homework, be sure to read the textbook sections and
the material in Learning Modules Five through Eight.
Type your solutions into this document and be sure to show all steps for
arriving at your solution.
MAT 230 Module Eight Homework
General:
Before beginning this homework, be sure to read the textbook sections and
the material in Module Eight.
Type your solutions into this document and be sure to show all steps for
arriving at your solution. Just givin
MAT 240
Module 2 Extra Credit Journal
Draw a histogram of DP05. Does DP05 have an approximately normal distribution? Does it have an
obvious skew (left or right) and any obvious outliers? If an analysis requires that DP05 have a normal
distribution, do yo
MAT 240
Module 4 Extra Credit Journal
A resident thinks that 15% of the months have no days with 0.5 inches or more of precipitation. Test
this claim at a 0.05 significance level. How do your results compare to your 95% confidence interval
from the Module
MAT 240
Module 1 Extra Credit Journal
Draw a histogram of TPCP. Estimate by eye the lowest and the highest data values from the graph (do
not calculate; instead, estimate from your graph). Are there any outliers?
Yes, there are some outliers in the data s
MAT 299 Module Five Homework
General:
Before beginning this homework, be sure to read the textbook sections and the
material in Module Five.
Type your solutions into this document and be sure to show all steps for arriving
at your solution. Just giving a