Design and Statistics
Chapter 4:
OVERVIEW:
If the scores in a distribution are all the same, then there is no variability; if there
are small differences between scores then the variability is small;
Design and Statistics
Chapter 5:
USING Z-SCORES TO STANDARDIZE A DISTRIBUTION:
It is possible to transform every X value in a distribution into a corresponding zscore, the entire distribution of X v
Design and Statistics
Chapter 5:
OTHER STANDARDIZED DISTRIBUTIONS BASED ON Z-SCORES:
It is common to standardize a distribution by transforming the scores into a new
distribution with a predetermined
Design and Statistics
Chapter 5:
INTRODUCTION TO Z-SCORES:
The purpose of z-scores, or standard scores, is to identify and describe the exact
location of every score in a distribution.
A score by it
Design and Statistics
Chapter 4:
TRANSFORMATIONS OF SCALE:
o Occasionally a set of scores is transformed by adding a constant to each score
or by multiplying each score by a constant value.
o The easi
Design and Statistics
Chapter 4:
1. STANDARD DEVIATION (SD)*
The most commonly used and the most important measure of variability.
SD used the mean of the distribution as a reference point and measu
Design and Statistics
Chapter 4:
STANDAR DEVIATION AND VARIANCE FOR SAMPLES:
The goal of inferential statistics is to use the limited information from samples to
draw general conclusions about popula
Design and Statistics
Chapter 6
Probability: a fraction or a proportion of all the possible outcomes for a situation
in which several different outcomes are possible.
o If the possible outcomes are i
Design and Statistics
Chapter 6
PROBABILITY AND THE NORMAL DISTRIBUTION:
Normal distribution is symmetrical, with the highest frequency in the middle and
frequencies tapering off as you move toward e
Design and Statistics
Chapter 7
Variability and Standard error serves two different purposes:
1. The standard deviation describes the distribution by telling whether the
individual scores are cluster
Design and Statistics
Chapter 7
PROBABILITY AND THE DISTRIBUTION OF SAMPLE MEANS:
The primary use of the distribution of sample means is to find the probability associated
with any specific sample.
o
Design and Statistics
Chapter 7
Larger populations and larger samples, the number of possible samples will
increase dramatically and it will virtually impossible to actually obtain every
possible ran
Design and Statistics
Chapter 7
SAMPLES AND POPULATIONS:
Sampling error: the natural discrepancy, or amount of error, between a sample
statistic and its corresponding population parameter.
The sampl
Design and Statistics
Chapter 6
Finding proportions/probabilities for specific z-score values:
o We begin with a specific z-score value and then use the unit normal table
to find probabilities or prop
Design and Statistics
Chapter 6
PROBABILITY AND THE BINOMIAL DISTIRBUTION:
When a variable is measured on a scale consisting of exactly two categories, the
resulting data are called binomial.
The te