Analyzing Data: Understanding Statistics

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what is a t-test?

Often used to test null hypothesis regarding observed difference between two means

the shape of distribution if the data in a frequency distribution are used to construct a figure called

frequency polygon

how is range of a set of scores calculated

highest score minus lowest score

Is the "range" or the "interquartile range" a more reliable statistic?

interquartile

what is another name for margin or error

confidence interval

sample size (t-test)

larger samples are less likely to have an observed difference based on sampling errors

t values rely on

degrees of freedom, which help to distinguish significance based on different amounts of data

which variable type corresponds to the outcome being measured

dependent variable

one way to describe a quantitative data is to prepare a

frequency distribution

what does r -1.00 indicate

perfect negative correlation. As one value goes up the other value goes down in a perfect line

Does a distribution with a tail to the right have a "positive" or a "negative" skew?

positive

in most population income has what type of skew

positive

a measure of how likely something is. In statistics, it considers how likely a random sample is to represent the true values if you asked the entire population.

probability

why is it important to know the scale of measurement when using statistical test

they largely determine the appropriate statistical test to carry out

Bivariate

two variables

Standard deviation measure

variability

dichotomous

variable is a categorical variable for which there are only 2 choices

a researcher ask is voting behavior differs based on one's race. Which of these variables is dependent?

voting behavior

The amount of variation in the population (t-test)

when a population is very homogeneous (similar), there is less potential for sampling error, so less variation leads to a lower p-value.

size of difference between means (t-test)

when the means being compared are more different, they are less likely to be explained by sampling error/lower value of p.

What is regression

widely used approach to statistical data analysis and looks at the linear association between two variables

what does r 1.00 indicate

a perfect positive correlation. As one value goes up the other value goes up in a perfect line

Do researchers reject the null hypothesis when the probability of its truth is high or when the probability is low?

low

Mathematical techniques used to analyze data that is numerical or that has been converted into number form AND based on the use of a sample drawn from the population (estimate value; m)

statistics

The null hypothesis says that true difference equals what numerical value?

0

Significance tests are designed to determine the probabilities regarding the truth of what hypothesis?

null hypothesis

N refers to

number of cases

Frequencies

number of times an answer was given by respondents.

when researchers study a sample are the results called the true results or the observed results

observed results

Chi-square test significant values vary and are based on

on degrees of freedom and significance in relation to the test's p-value (typically .05).

Univariate

one variable

if al individual in a group have the same score what is the value of the standard deviation for the score

0

what is the base for proportions

1

The Chi-square test ask?

"how likely is it that an observed distribution is due to chance (null hypothesis)?

percentage for different groups are exposed on a common scale with what base

100

α ≤ .05 (5%) means confidence level

95%

how is the mean calculated

Add up the scores and then divide by the number of scores

ordinal definition

Answers have a rank order with no specified distance between each category

"Pearson r" stands for what words?

Pearson product-moment correlation coefficient

What is confidence level

Percentage of all possible samples that could include the true population parameter within a suggested range

The expression p<.05 stands for what words?

The probability that the null hypothesis is correct is less than 5 in 100.

Type II Error

When the researcher fails to reject the null hypothesis but it should have been rejected.

when the relationship between two variables is perfect and inverse, what is the value of r?

-1.00

what causes t-test to yield low probability?

-sample size -size of difference b/w means -amount of variation in the population

If 600 individuals in a population of 1,000 are Democrats, what is the corresponding percentage of Democrats?

60%

in a normal distribution, what percentage lies within one standard deviation unit of the mean

68%

α ≤ .01 (1%) means confidence level is

99%

what does regression tries to answer?

How much variation in the dependent variable can be explained by variation in the independent variable(s)?"

what branch of statistics helps researchers to estimate the effects of sampling errors on their results

Inferential

what is Person correlation coefficient

Measures degree of linear correlation between two variables

what is Chi-square test

Tests for differences between frequencies of values that are observed versus those that were expected.

what is the formal definition of the mean

The value around which the deviations sum to zero

Type I error

When the researcher rejects the null and concludes that a study supports the research hypothesis when the null is in fact correct.

what is the term for the cutoff value that is commonly used in statistics to set limit for accepting that the results from a statistical test are due to change?

alpha < or = to 0.5

ANOVA stands for

analysis of variance (F)

do researchers use univariate or bivariate analyses to examine the relationship between 2 nominal variables

bivariate

what value is 100 minus the alpha

confidence level

Two-way ANOVA

considers whether differences when researchers use a two-way classification

which brand of statistics helps researchers to summarize data so they can be easily comprehended and is a frequency distribution?

descriptive

is a relationship direct or inverse when those with high scores on one variable have high scores on the other AND those with low scores on one variable have low scores on the other?

direct

What is the interquartile range?

divides a sample of any size into quarters, then cuts off the top and bottom quarter, looking at only the middle 50%

statistics use a sample to make __ about a population

inferences

Are significance tests associated with "descriptive" or "inferential" statistics?

inferential

Which two scales of measurement have equal distances among the scores they yield?

intervals and ratio

Which average is defined as the balance point in a distribution?

mean

which average is usually reported when the standard deviation is reported?

mean

what is null

means zero, empty, or nothing

what is the synonym for the term average

measure of central tendency

Should the "mean" or the "median" be used with ordinal data?

median

which one of the three averages is very seldom used in formal reports of research AND is defined as the most frequently occurring score?

mode

when researchers use a large sample, are they more likely or less likely to reject the null hypothesis than when a researcher uses a small sample?

more likely

ANOVA can compare

more than 2 means

if a descriptive statistics involves more than 2 variables what is it called

multivariate

if a distribution has some extreme scores on the right but not on the left it is said to have what type of skew

negative

if a distribution is skewed to the left, does it have a positive or negative skew

negative

what does the null hypothesis say about difference between two sample means

no true differences b/w the means b/c the values are the results of the chance errors created by random sampling or sampling errors

if researcher asks participants to name country in which they were born, the researcher is using which type of scale measurement

nominal

what is the name of the curve that is symmetrical

normal curve

the "bell curve" is a nickname for what

normal distribution

When data from the entire population are analyzed, the resulting values are called (actual value; M)

parameter

what is the name of the statistic that describes how many participants per 100 have certain characteristics AND proportion of respondents that gave each type of response?

percentage

a researcher asks if voting behavior differs based on one's race. Which of these variables is independent?

race

Does the term sampling error refer to "random errors" or to "bias?"

random errors

what statistics discussed are measures of variability

range and interquartile range

Mean

same as average: summarizing a single variable by adding all values and dividing by the number of values

the observed difference (null hypothesis) was created by

sampling error

What is an alternative way of saying a researcher has rejected the null hypothesis?

statistically significant

By studying samples, do researchers obtain "statistics" or "parameters"?

statistics

One-way ANOVA

tests the influence of only one independent variable (IV) on the dependent variable (DV).

a null hypothesis suggest that

that the result of study or experiment shows that results were not significant.

what is meant by term variability

the amount by which participants vary or differ from each other

Median

the middle value when all values are ordered from smallest to largest

what is one incorrect way of saying a researcher has failed to reject the null hypothesis.

the researcher should not say they accept the null hypothesis

If an ANOVA yields p<.05, should the null hypothesis be rejected?

yes 0.5 or less

nominal definition

•Answers are names not numbers with no meaningful rank order

ratio definition

•Answers have a rank order with a specific distance and a zero that equals "none" of the characteristic

Interval definition

•Answers have a rank order with a specific distance but no zero that equals "none" of the characteristic

what is ANOVA

•Compares the means of two groups to see if they truly reflect a difference.

What is descriptive statistics?

•Describes or summarizes data •May describe one variable or the relationship between two or more variables

What is inferential statistics?

•Infers or estimates how well sample data represent the population •Used to generalize results to the population •Presents the statistic as well as its likelihood of being an accurate estimate


Ensembles d'études connexes

Chapter 2 cross sectional anatomy

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