Terms  Definitions 

event 
each unique outcome

the mean of binomial distribution 
u=np

Unimodal 
Distribution only has one hump

Mode 
The score that occurs most frequently...remember, it is possible to have a bimodal or multimodal distribution.

OneTailed test 
Statistical hypotheses specify either an increase or a decrease in the population mean score. AKA Makes a statement about the direction of the effect

population 
the entire collection of events that you are interested in

Continuous Scale 
Allows for fractional amounts; it continues between the wholenumber amounts.

Zscores 
How many standard deviations a score is from the mean, normal distributions range from 3 to +3

power 
he probability of selecting a mean from Mean Distribution 2 and having that mean be above the critical value for distinguishing it from Mean Distribution 1

Most statistics in use in psychology are 
Inferential

Internal validity 
Measures the extent to whcih the different items within a measure "hang together" and test the same thing

Criterionreference tests 
Measure mastery in a particular area or subject

mean 
indicates the point on the scale of measures where the population is centered.the average of the scores in the population. Numerically, it equals the sum of the scores divided by the number of scores.

Spread/Dispersion/Variability 
Indicates how the scores are around the central point. he data values in a sample are not all the same. This variation between values is called dispersion.When the dispersion is large, the values are widely scattered; when it is small they are tightly clustered

hypothesis testing calculates 
the probability that the differences are due to random variability (i.e., the first option or the Null Hypothesis)

alpha level 
a result is due to chance if probability is greater than the alpha level, it is nonchance if less than the alpha level .. Its statistically significant!

External validity 
The extent to which a test measures what it intends to measure (4 aspects of external validity)

an interval scale 
he distance between any two adjacents units of measurement is the same but the zero point is arbitrary. eg. temperature 30 degrees more than 40 degreesie. heights of tides, and the measurement of longitude.

the probability of a Type II error is _______. 
Beta

descriptive statisticsalpha and the number of tails. If alpha = .05 and we are using a twotailed test, then the critical value is 1.96 (from the Z tables). 
the science of describing distributions of samples or populations

standard deviation of a binomial distribution 
= sq root of npq

one tail left 
prior evidence u less than aHo: u greater than or = to aH1: u less than a

If the tvalue exceeds critical value, 
the null hypothesis is rejected

type II error 
You have committed a this error if you have failed to reject the hypothesis...u thought it was true hyp...it was not

comparison distributions are used.. 
are used to compute the probability of the obtained sample result under the assumption that the null hypothesis is true

assumptions of the one sample ttest 
1. the sample is randomly and independently selected from the population. 2. the scores on the variable are normally distributed in the population

What happens in Type II error? 
No research report is created, Not much loss to the scientific community, Loss to researcher, Other researchers can still find the effect

sampling error, why does it occur 
will occur b/c sample data is only based on a portion of the population, so sample stats may differ from the value of its corresponding population parameter

What happens when a distribution is standardized? 
Transforming all x's into z scores. Mean of 0. Standard deviation of 1

What does it show if we reject our null? 
we have shown evidence that it is likely to be untrue

Leave a Comment ({[ getComments().length ]})
Comments ({[ getComments().length ]})
{[ comment.comment ]}