Stats Flashcards
The Average: add all numbers and divide by how many numbers you have
Mean
When you put all the numbers in order and find the middle number
Median
Most frequent number
Mode
Highest # minus Lowest # is the:
Range
Highest # minus Lowest # +1 is:
Inclusive Range
Pearson’s Product Moment Correlation Coefficient is shown as:
r
r2 =
shared variance
This is the variable you can manipulate in an experiment:
Independent Variable
This is the variable you measure in an experiment:
Dependent variable
How flat or peaked a distribution is called:
Kurtosis
A flat distribution is called:
platykurtic
A peaked distribution is called:
Leptokurtic
When there is a lack of symmetry in a distribution, it’s called:
skewed
A positive skewed distribution has a tail on the:
positive end of the distribution (right side)
A negatively skewed distribution has a tail on the:
negative end of the distribution (left side)
this scale of measurement uses names/categories:
Nominal
This scale of measurement uses ranks (1st, 2nd, 3rd)
Ordinal
This scale of measurement uses point along the sale that are equal. This also has no absolute zero
Interval
This scale of measurement has a presence of absolute zero
Ratio
What type of correlation do you use when looking at 2 nominal variables (ex: voting preference, such as Republican or Democrat)
a) Rank Biserial
b) Point Biserial
c) Phi Coefficient
d) Pearson Correlation Coefficient
e) Spearman rank coefficient
c) Phi Coefficient
(nominal & nominal)
What type of correlation uses a nominal and ordinal scale? (ex: correlation between social class and rank in high school):
a) Rank Biserial
b) Point Biserial
c) Phi Coefficient
d) Pearson Correlation Coefficient
e) Spearman rank coefficient
A) Rank Biserial
What type of correlation uses nominal and interval scales (ex: looking at the difference between car ownership and age)
a) Rank Biserial
b) Point Biserial
c) Phi Coefficient
d) Pearson Correlation Coefficient
e) Spearman rank coefficient
B) point biserial
What correlation uses ordinal and ordinal scales? (ex: correlation between height and weight):
a) Rank Biserial
b) Point Biserial
c) Phi Coefficient
d) Pearson Correlation Coefficient
e) Spearman rank coefficient
e) spearman rank coefficient
What correlation uses interval and interval scales of measurement? (ex: the correlation between number of problems solved and age in years).
a) Rank Biserial
b) Point Biserial
c) Phi Coefficient
d) Pearson Correlation Coefficient
e) Spearman rank coefficient
D) Pearson Correlation Coefficient
(Cohen’s d) coefficient strength of .8 is
a) low
b) medium
c) high
d) none
c) high
(Cohen’s d) Coefficient strength of .5 is:
a) low
b) medium
c) high
d) equal
b) medium
(Cohen’s d) Coefficient strength of .2 is:
a) low
b) medium
c) high
d) non-existant
a) low
a positive correlation is also known as a(n):
-direct correlation or
-indirect correlation
Direct correlation
a negative correlation is also known as a(n):
-direct correlation or
-indirect correlation
indirect correlation
On what type of chart do bars touch each others?
histogram
On what type of chart do the bars not touch?
Bar graph
What type of chart uses trends in data at equal intervals?
Line chart
What type of chart or graph is made with nominal variables?
Pie graph
If your obtained value (ov) is more extreme than the critical value (cv), do you:
a) accept the null hypothesis, b) reject the null hypothesis, c) fail to reject the null hypothesis?
Reject the null hypothesis
If your obtained value (ov) is less extreme than the critical value (cv) do you:
a) accept the null hypothesis
b) reject the null hypothesis
c) fail to reject the null hypothesis
c) fail to reject the null hypothesis
This test tells you the difference between 2 or more groups:
ANOVA
How do you solve for degrees of Freedom?
n-1
Type I error:
a) False negative
b) False positive
b) false positive
ex: The pregnant woman’s Alpha-Fetoprotein Test wrongly indicates that patient has down syndrome, which means that pregnancy must be aborted for no reason
Type II error:
a) False negative
b) False positive
a) False negative
ex: The pregnant mom’s Alpha-Fetoprotein Test is negative and the child will be born with multiple anomalies
The probability of rejectin a null hypothesis when it’s true is known as what type of error?
Type I error
The probability of accepting a null hypothesis when it is false is know as what type of error
Type II error
How well a test measures what is says it does is called:
Validity
The consistency of a test is known as:
Reliability
A test for the difference between two or more means:
Analysis of Variance
Type of validity that examines how well a test samples a universe of items
Content validity
The best estimate of the range of a population value given the sample value:
Confidence interval
Numerical index that reflects the relationship between 2 variables, specifically how the value of ones changes when the value of the other changes
Correlation coefficient
Type of validity that examines how well a test reflects some criterion that exists in either the present or the future
criterion-based validity
Research design used to explore more than one treatment variable:
Factorial design
Type of reliability that examines whether items on a test measure only one dimension, construct, or area of interest
Internal consistency reliability
A type of reliability that examines whether observers are consistent with one another
Interrater reliability
The mean, median, and mode are known as the:
Measures of Central Tendency
This test compares a sample mean to a population
one sample z-test
a sample is a:
subset of a population
a type of reliability that examines a test’s consistency over time
test-retest reliability
a raw score that is adjusted for the mean and standard deviation of the distribution from which the raw score comes:
z score
Used to find if theres a difference in the average scores of one or more variables between 2 groups:
Independent means t test
a third variable is sometimes called a ___________ variable:
Confounding
In a normal curve, what percent of scores fall between the mean and -1 standard deviation?
34%
What percent of scores land between the mean and -1 and +1 standard deviations in a normal curve?
68%
what percent of scores fall between the mean and +2 and -1 standard deviations in a normal curve?
-1 mean +1 +2
82% of scores
What percent of scores fall between the mean and 2 standard deviations (both positive or both negative) on a normal curve?
~ 47.72 or 48%
the percent of scores that fall between the mean and -2 and +2 SD on a normal curve is:
95 % of scores
a positive z score falls to the ___________ of the mean:
a) left
b) right
b) right
a negative z score falls to the _______ of the mean:
a) left
b) right
a) left
a z score is simple the number of _________ _________ away from the mean
Standard deviations
if your z score is +1 then the area between the mean and z is what percent on a bell curve?
34%
a z score of 2.5 is what percent of scores on a bell curve?
49.38%
this is a standard score that is computed by multiplying the z score by 10 and adding 50
t score
When you reject the null hypothesis when the null hypothesis is actually true:
Type I error
When you accept the null hypothesis when the null hypothesis is really false:
Type II error
If the level of significance is .05, what percent chance do you have of rejecting the null hypothesis when it’s true and there really is no group difference?
5%
This type of error is sensitive to the number of subjects in a sample; as a sample increases, the probability of this error decreases
Type II error
The probability of a raw score falling withing +/- 1.96 z scores or standard deviations is:
95%
Probability of a raw score falling within +/- 2.56 z scores or SD’s is:
99%
A _____ test is a sample and a population
z test
a ____ test is two groups/samples
t test
What’s the difference between a dependent and independent samples t test
dependent = pre/post, 2 groups are related/same; independent is that they are not the same group
How well a test can detect and reject a null hypothesis when it is false is known as:
power
when your z value is more extreme that the critical value do you reject or fail to reject the null hypothesis?
REJECT THE NULL
When the z value is below the critical value do you reject or fail to reject the null hypothesis?
fail to reject the null (less extreme)
When you want to test a group twice after an intervention to see how they improve, you’d use what kind of ANOVA?
Repeated measures ANOVA
If the correlation between two variables in .47, how much variance is accounted for?
.47 squared = .2209; 22.09% accounted for
The line of best fit is known as a __________ line
regression
