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