COMM 308 exam 2

compares multiple groups with three variables

MANOVA

The measures of central tendancy

Mean, medium, mode

help us generalize about a wider population from a smaller sample of it

inferential statistics

looking at the "middle ground" of dispersion. the range of the middle 50%

interquartile range

the probability of a calculated value occuring. the larger the sample, the more confident we are.

confidence level

provides a measure of the strength of relationships between 2 or more variables

correlation

respondents are asked to locate their level of agreement somewhere between strongly agree and strongly disagree

likert scale

(number of scores in group1 -1) + (number of scores in group 2 - 1)

degree of freedom

respondents select from one of two possible answers

dichotomous questions

strives to obtain samples that statistically represent the overall population.

probability samples

statistical method for estimating how the value of one variable will change given changes in another variable

regression

presents a topic, followed by scales anchored at each end by words or phrases that have opposite meanings

semantic differential scale

difference between the groups will differ

two tailed test

use 2 groups of students and only place one group into group study sessions. if the students in the study sessions show a measurable change in test scores and the control group does not, we can be more confident that the study sessions have an effect.

two-group pretest-posttest design

deciding wrongly that there was a significant result, when there was not

type 1 error

deciding wrongly that there was not a significant result, when there actually was

type 2 error

standardize different measures so that we can compare them "on a level playing field."

variance and standard deviation

Difference between descriptive statistics and inferential statistics

• Descriptive statistics are used to describe and summarize the data from a research sample. Inferential statistics help us make probability-based inferences about the wider population from which we obtained our sample. • Descriptive statistics help simplify and understand research data. Inferential statistics answers the major question of "to what extent do my sample data reflect the wider population from which I obtained my sample?"

difference between the groups will be in one direction

one tailed test

basic experimental design consists of a baseline observation, followed by exposure to an experimental condition, followed by postexperminetal observation to see if any change has occurred in the experimental group.

one-group pretest-posttest design

respondents answer in their own words

open ended questions

compare multiple groups with 2 variables

ANOVA

the measures of dispersion

max, min, range, interquartile range, variance, standard deviation

describe central features of a data set

measures of central tendancy

describe the range and variability of scores

measures of dispersion

not statistically representative of wider population- but may have greater relevance

non probability samples.

square root of the variance

standard deviation

compares mean scores of 2 groups on the same variable to determine probability that the groups are different

t-test