Test 1 (Stats)

Cohen's cut offs for "r"

< .1: Trivial >/= .1: Small >/= .3: Medium >/= .5: Large

d-statistic cut offs

< .2: trivial >/= .2: small >/= .5: medium >/= .8: large

d-statistic Song

A d-stat says how far apart two means are split measured with a standard deviation unit

Cronbach's alpha cut offs

.80 = good .70 = adequate <.70 = poor

With a positive z-score

1-the score in the table is the answer

In class, we discussed two key questions that could be addressed if Moniz had conducted a clinical trial. What are those questions?

1. How big is the effect? Effect size (descriptive) 2. Could it be a random chance? (Inferential)

Normal Distribution

2% 14% 34% 34% 14% 2%

A word that means: "if the null hypothesis is true, then the results from the sample are extremely unusual."

Significant

Bruno computed a standard deviation, but he accidentally used "n" rather than the degrees of freedom in his formula. This means that the value he obtains will be ____________________ .

Smaller than the actual value

What commonly calculated statistic is essentially the mean of |ei| ?

Standard deviation

If this study were repeated over and over, what is the typical amount of sampling error that would be made in each study?

Standard error (SDx-bar)

The general term for a numerical value based on data from a sample (that may indicate something about the sample or something about the population).

Statistic

An effect size that is typically used with two numerically scales variables.

r

If both x and y are z scores (sd=1), then....

r(xy) = Cov(xy)

This is equal to true variance.

(SD)^2 - (SDmeasure)^2

What shape should the most negative possible covariance produce?

A square

What shape should the most positive possible covariance produce?

A straight line

t-value song

A t-value is always where You divide a stat by it's standard error

The probability of committing a type I error if the null hypothesis is true.

Alpha

This statistic describes a distribution that becomes almost perfectly normal in shape as the sample size increases beyond 30.

SDx-bar

This will become smaller as the sample size increases.

SDx-bar

The set of cases from which a researcher collects data.

Sample

The probability of committing a type II error if the null hypothesis is false.

Beta

The term used when the expected value is not equal to the parameter.

Bias

What is a limitation of correlational research?

Cannot be used to determine cause

What is a limitation of experimental research?

Cannot be used to explain natural phenomena

The association between clinician confidence and accuracy What is the name of the statistic? What is the value of the effect size?

Correlation .1

The association between therapeutic alliance and psychotherapy outcome What is the name of the statistic? What is the value of the effect size?

Correlation .3

The association between self-compassion and (lack of) psychopathology What is the name of the statistic? What is the value of the effect size?

Correlation .5

Formula for correlation

Correlation = covariance/averaged variance r(xy) = cov(xy)/(SDx)(SDy)

A type of research that involves observing that which occurs naturally without manipulation.

Correlational Research

What percent of the total variance is true variance?

Cronbach's alpha

A numerical value based on data from a sample that indicates something about the sample.

Descriptive Statistic

Standard error of the correlation reflects:

Deviations around a population parameter

Standard error of the mean difference reflects:

Deviations around a population parameter

Standard error of the mean reflects:

Deviations around a population parameter

Standard error of estimate reflects:

Deviations around a predicted value

Standard deviation reflects:

Deviations around a sample mean

Standard error of measure reflects:

Deviations around a true score

"More Extreme"

Double the score for higher/lower

The average of all the values for a population of values from which a single value can be randomly sampled.

Expected Value

A type of research that involves manipulation and random assignment.

Experimental Research

Area under the normal distribution curve

Gives probability

What is ei?

How much case i deviates from the mean <-- Not an absolute value

Mean Song

If you pick someone at random and you want to bet The mean is the score you expect to get

A numerical value based on data from a sample that indicates something about a population.

Inferential Statistics

In the process of computing a standard deviation, Zelda lost one degree of freedom. What did Zelda do that caused her to lose one degree of freedom?

Lost one subject from her total "n" I.e. with a sample of 7, she would have 6 degrees of freedom - a sample of 6 would render 5 degrees of freedom. To lose one degree of freedom would be equivalent to losing one participant from her sample.

The assumption that the population parameter for a statistic is equal to zero.

Null Hypothesis

Standard error of measure pertains to:

Observations of a single case

Standard deviation pertains to:

Observations of different cases

Standard error of estimate pertains to:

Observations of different cases

Standard error of the correlation pertains to:

Observations of different samples

Standard error of the mean difference pertains to:

Observations of different samples

Standard error of the mean pertains to:

Observations of different samples

A numerical value based on data from all the cases in a population that describes something about the population.

Parameter

All of the cases in which a researcher is interested.

Population

The probability of making a correct decision if the null hypothesis is false.

Power

The extent to which a measured value stays the same regardless of how, when, or where it is measured.

Reliability

This is the standard error of measure.

SD(sq. root (1-reliability))

This value will become smaller as the effect size increases.

SDest

If an individual was assessed on repeated occasions, how much would each of her observed scores typically deviate from her true score?

SDmeas = sd (sq. root (1-reliabiltiy)) Reliability = Cronbach's alpha

Pooled Standard Deviation Formula

SDpooled = (sq. root (SSone + SStwo)/(DFone + DFtwo))

Xi hat

The mean for any case "i"

With a negative z-score

The score in the table is accurate

What is xi?

The score on x for case i

Standard Deviation Song

The standard deviation is used to measure things It's how far the average person strays from the mean

Another component of the t-formula is something that is calculated from the sample, and if we knew the true population parameter for this, the distribution would change from a t-distribution to a z-distribution. What is this value?

The standard error (SDx-bar)

Given the assumed value for the population parameter, what is the value that indicates the amount of sampling error that was made in this study?

The statistic (the mean)

One component of the t-formula is something that is calculated from the sample, and if we knew the true population parameter for this, there would be no reason for doing the t-test. What is this value?

The statistic (the mean)

A person's average score on a test if he or she were assessed an infinite number of times.

True Score

The extent to which a scale measures what it is supposed to measure.

Validity

Given the assumed value for the population parameter, the error in this study is equal to the typical error times what value?

Y where (SDx-bar) * Y = x-bar

In the t-statistic formula, what is the assumed value for the population parameter?

Zero

The probability of committing a type I error if the null hypothesis is false.

Zero

What is the mean of ei?

Zero

This is estimated by Cronbach's alpha.

[(SDtrue)^2]/(SD)^2

This is estimated by a correlation between two alternate forms.

[(SDtrue)^2]/(SD)^2

This is estimated by a test retest correlation.

[(SDtrue)^2]/(SD)^2

What percent of the total variance is measurement error variance?

[(sd)^2 - (alpha - sd^2)]/(sd)^2

An effect size that is typically used when one variable is dichotomous.

d

d-statistic formula

d = (x-bar1 - x-bar2)/(SDpooled)

The effectiveness of cognitive behavior therapy with motivational interviewing for treating alcohol use disorder What is the name of the statistic? What is the value of the effect size?

d-statistic .2

The effectiveness of dialectical behavior therapy for treating borderline personality disorder What is the name of the statistic? What is the value of the effect size?

d-statistic .4

The effectiveness of cognitive therapy for treating depression What is the name of the statistic? What is the value of the effect size?

d-statistic .8

The effectiveness of prolonged exposure for treating PTSD What is the name of the statistic? What is the value of the effect size?

d-statistic 1.0

A standard error of measure indicates the typical deviations for _____ from the linear equation _______ where the subscripts ________

e(ai) x(ai) = true(i) + e(ai) a and is and for assessment occasion and individual

Standard deviation indicates the typical deviations for ____ from the linear equation _____ where the subscripts ______

e(is) x(is) = x-bar(s) + e(is) i and s stand for individual and sample

A standard error of estimate indicates the typical deviations for _____ from the linear equation _______ where the subscripts ________

e(is) y(is) = prediction based on x(is) + e(is) i and s stand for individual and sample

A standard error of a mean indicates the typical deviations for _____ from the linear equation _______ where the subscripts ________

e(sp) x-bar(sp) = mu(p) + e(sp) s and p stand for sample and population

A standard error of a mean difference indicates the typical deviations for _____ from the linear equation _______ where the subscripts ________

e(sp) (y-bar - y-bar)(sp) = (mu - mu)(p) + e(sp) s and p stand for sample and population

A standard error of the correlation indicates the typical deviations for _____ from the linear equation _______ where the subscripts ________

e(sp) r(sp) = rho(p) + e(sp) s and p stand for sample and population

Two distributions of sampling error that are skewed in shape.

f and X^2

A distribution of sampling error that is almost normal in shape.

t

t-value formula

t = ((x-bar) - population parameter)/(SDx-bar) t = [statistic (sample mean) - parameter (null hypothesis)]/SDstatistic

What value is xi-hat equal to?

x-bar