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data sets with continuous, categorical, grouped and correlated data. Great
for creating data sets for examples and for quality assurance testing. Data
sets are created in standard .CSV format so they can be opened in most
statistical programs such as SAS, SPSS, WINKS and into spreadsheet programs
such as Microsoft Excel.
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These WINKS statistics tutorials
explain the use and interpretation of standard statistical analysis
techniques for Medical, Pharmaceutical, Clinical Trials, Marketing or Scientific
Research. The examples include howto instructions for WINKS SDA Version 6.0
Software. Download evaluation
copy of WINKS.
Single Sample ttest
Definition: Used to compare the mean of a sample to a known number
(often 0).
Assumptions: Subjects are randomly drawn from a population and the
distribution of the mean being tested is normal.
Test:
The hypotheses for a single sample ttest are:
H_{o}:
u = u_{0}
H_{a}:
u < > u_{0}
(where u_{0}
denotes the hypothesized value to which you are comparing a population mean)
Test
statistic: The test statistic, t, has N1 degrees of freedom, where N is
the number of observations.
Results
of the ttest: If the pvalue associated with the ttest is small
(usually set at p < 0.05), there is evidence to reject the null hypothesis
in favor of the alternative. In other words, there is evidence that the mean
is significantly different than the hypothesized value. If the pvalue
associated with the ttest is not small (p > 0.05), there is not enough
evidence to reject the null hypothesis, and you conclude that there is
evidence that the mean is not different from the hypothesized value.
Example:
Single Sample ttest
You read in
an article that an educator claimed that the average educational level for
people over 60 in was 8th grade. You happen to have a data (ELDERLY.DBF)
that contains a random sample of elderly people, and you want to test the
educator's claim. The results of performing a single sample ttest are:



Single Sample ttest



Variable Name is EDUC


N = 166 Missing or Deleted = 0

Mean = 10.07831 St. Dev (n1) = 3.25109


Null
Hypothesis: mean(POPULATION) = 8


Calculated t = 8.24 with 165 D.F. p = < 0.001 (2  sided test)


95%
C.I. about Mean is (9.57995, 10.57667)


A
low value of p supports rejection of the null hypothesis.

There is evidence that the actual mean is different from the

hypothesized mean.
Exercise
 Single Sample ttest
You have
been told that the average employee for your industry has an average
dexterity score of 100 on a standardized test. You think your employees will
score differently, so you give a random sample of 12 the test. The results
are:
Subj. Test Score
1 98
2 102
3 120
4 140
5 123
6 101
7 89
8 99
9 119
10 103
11 132
12 107
1. Perform
a single sample ttest on this data.
2. What are
your hypotheses?
3. What
conclusion do you make?
4. Use the
Detailed Statistics option to calculate a 95% confidence interval on the
mean. How does this approach differ from doing the ttest?
Do this analysis NOW using WINKS
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"Best value for an easy to use and
extensive statistical program."
Basic edition starts at $99.
Student editions also available.
"Winks is an excellent basic program that runs well on my
laptop. I find that I use it more than SAS"  Dr. Jim Dickson, Iowa
State University

Statistical Software
designed for your needs  Medical, Clinical Trials, Dissertation, Thesis,
Business, Marketing, Agriculture, Forestry, Science and Research.

WINKS is an
economical, reliable and simple to use statistical analysis tool designed
to help students and researchers get the statistical answers they need
quickly and without hassle.

It contains a wide
range of statistical tests including many handy features not found in
programs such as SPSS or SAS  for example, easy analysis from summary
data (as well as from raw data), nonparametric multiple comparisons,
APA standard analysis writeup suggestions and more.

Newest additions to
WINKS (ver 6.05) includes Grubbs Test for outliers and Tukey Test
for outliers, Kwikstat Data Generator evaluation edition,
multiple comparisons in 2xc and rx2 crosstabulation (ChiSquare)
analysis) & Permutations and combinations calculator

Statistical test such as
ttests (paired t test, independent group t test/unpaired t test),
ANOVA, regression, correlation, repeated measures,
logistic regression, times series analysis, chisquare,
BlandAltman, KruskalWallis, MannWhitney and much
more.

Friendly interface with
easy Excellike data handling & graphs (reads and writes Excel files.)

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delivery to you when you order now

Print a brochure (pdf
format)

Recent updates include
 Added ability to calculate new column of zscores for numeric
variables.
 Increased maximum groups to 40 for oneway ANOVA and oneway
repeated measures (40 repeats).
 Added editor option to create indicator variables from categorical
variables.
 Added Outcomes and Probabilities module that calculates combinations
and permutations.
 Added Grubbs & Tukey tests for outliers.
 Added Multiple Comparisons of Proportions to Crosstabulations
procedures for 2xc or rx2 tables
 Updates are free to current users.
Read more about WINKS features.
Download WINKS Evaluation
Version Now
For more information... we
recommend:

WINKS  a simple to use and
affordable statistical software program that will help you analyze,
interpret and writeup your results. Download a free trial copy.

Additional statistics
tutorials.

Against All Odds VIDEOS  Now in VHS or DVD formats
Teaching Videos from
Annenberg/PBS
Click here for info

BeSmartNotes Reference sheets for SAS, SAS ODS, SPSS and WINKS
 Click here for info.
(www.besmartnotes.com)

Statistical Analysis Quick Reference
Guidebook: With SPSS Examples is a practical "cut to the
chase" handbook that quickly explains the when, where, and how of
statistical data analysis as it is used for realworld decisionmaking
in a wide variety of disciplines. It contains examples using SPSS
Statistics software. In this onestop reference, the authors provide
succinct guidelines for performing an analysis, avoiding pitfalls,
interpreting results, and reporting outcomes. Paperback. Sage
Publishers ISBN: 1412925606
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