STATISTICS FOR THE BEHAVIORAL
SCIENCES 10TH EDITION GRAVETTER
EXAM REVIEW TESTED QUESTIONS WITH
100 PERCENT CORRECT ANSWERS
◉ Standard Deviation
Answer: The positive square root of the variance and PROVIDES A
MEASURE OF THE AVERAGE DISTANCE FROM THE MEAN.
◉ What does a Standard Deviation of zero mean?
Answer: When the Standard Deviation equals zero, it means that
there is no variability in the scores.
*The higher the values of the Standard Deviation, the more
variability there is, everything else being equal.
◉ Z-Score
Answer: The distance a raw score is from the mean when measured
in units of standard deviation.
◉ What do Z-Scores do?
,Answer: Z-Scores allow us to determine the raw scores location in a
distribution, it's relative and simple frequency, and its percentile
◉ Important characteristics of z-Scores
Answer: *A z-Score of 0 is equal to the Mean of the raw score
*A positive z-score indicates the raw score is greater then the mean,
a negative z-score indicates the raw score is less than the Mean
*The larger the absolute value of a z-score, the less frequently that
raw score occurs
*The standard deviation and variance of a set of standard scores
always equals 1.00
*Even though the measures of central tendency and variability will
change when you convert to standard scores, the shape of the
distribution does not change
*68% of the scores in a normal distribution will be +/- 1 z-score
*95% of the scores in a normal distribution will be +/- 2 z-scores
◉ Power
Answer: The probability that the test will correctly reject a false Null
hypothesis. That is, the power is the probability that the test will
identify a treatment effect if one really exists.
◉ What is effect size?
, Answer: provides a measurement of the absolute magnitude of a
treatment effect, independent of the size of the sample being used
◉ One-Tailed Test
Answer: Directional tests. result in significantly more power because
it increases the critical region in one direction
◉ Null Hypothesis
Answer: A Null Hypothesis states that in the general population
there is no change, difference, or relationship between the two
variables
*Symbol for the Null Hypothesis = Ho
◉ What does the Null Hypothesis do?
Answer: *In the context of an experiment, Ho predicts that the IV
(treatment) has no effect on the DV (Scores) for the population
*Provides a starting point for any statistical test
◉ Alternate Hypothesis
Answer: The Alternate Hypothesis states that there is a change,
difference, or relationship for the general population
*H1
SCIENCES 10TH EDITION GRAVETTER
EXAM REVIEW TESTED QUESTIONS WITH
100 PERCENT CORRECT ANSWERS
◉ Standard Deviation
Answer: The positive square root of the variance and PROVIDES A
MEASURE OF THE AVERAGE DISTANCE FROM THE MEAN.
◉ What does a Standard Deviation of zero mean?
Answer: When the Standard Deviation equals zero, it means that
there is no variability in the scores.
*The higher the values of the Standard Deviation, the more
variability there is, everything else being equal.
◉ Z-Score
Answer: The distance a raw score is from the mean when measured
in units of standard deviation.
◉ What do Z-Scores do?
,Answer: Z-Scores allow us to determine the raw scores location in a
distribution, it's relative and simple frequency, and its percentile
◉ Important characteristics of z-Scores
Answer: *A z-Score of 0 is equal to the Mean of the raw score
*A positive z-score indicates the raw score is greater then the mean,
a negative z-score indicates the raw score is less than the Mean
*The larger the absolute value of a z-score, the less frequently that
raw score occurs
*The standard deviation and variance of a set of standard scores
always equals 1.00
*Even though the measures of central tendency and variability will
change when you convert to standard scores, the shape of the
distribution does not change
*68% of the scores in a normal distribution will be +/- 1 z-score
*95% of the scores in a normal distribution will be +/- 2 z-scores
◉ Power
Answer: The probability that the test will correctly reject a false Null
hypothesis. That is, the power is the probability that the test will
identify a treatment effect if one really exists.
◉ What is effect size?
, Answer: provides a measurement of the absolute magnitude of a
treatment effect, independent of the size of the sample being used
◉ One-Tailed Test
Answer: Directional tests. result in significantly more power because
it increases the critical region in one direction
◉ Null Hypothesis
Answer: A Null Hypothesis states that in the general population
there is no change, difference, or relationship between the two
variables
*Symbol for the Null Hypothesis = Ho
◉ What does the Null Hypothesis do?
Answer: *In the context of an experiment, Ho predicts that the IV
(treatment) has no effect on the DV (Scores) for the population
*Provides a starting point for any statistical test
◉ Alternate Hypothesis
Answer: The Alternate Hypothesis states that there is a change,
difference, or relationship for the general population
*H1
