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What is this? ΣfX/N
Mean = Average
sum of the scores and divide by the number of scores
Balances the distribution in terms of score values
What is this? Σf(X-M)2 /N
this is the sum of squares; sum of squared deviation scores. variance of a sample
Estimate of population variance
For what purposes would you use a bar graph?
For what purposes would you use a histogram?
Used for continuous variables, value is at the midpoint of each bar. used to show continuous data
For what purposes would you use a frequency polygon?
Like a histogram without bars. Used for continuous variables. Line is used to connect the midpoints of each variable. used when you have continuous data.
What measure of central tendency equally divides a distribution?
Median, middle value.
What shows the frequencies of each values within a variable?
What is this? X–M/ SD
What shows frequencies for grouped values within a variable?
grouped frequency distribution
What is the area of the normal distribution between -1 SD and +1 SD? Explain.
Mean, median, and mode because they’re value is identical / 68%
What is a distribution where mean, median and mode are the same value?
Normal Distribution. (symmetrical distribution)
What is the SD divided by the square root of N?
Estimate of the standard error of the mean.
What is the general term for a characteristics of the population?
What is the general term for a characteristics of a sample?
Describe: Type 1 error.
Probability of rejecting the null hypothesis when it is true
When you fail to reject the null and the null is trueIs acceptable at <5%
Probability of accepting the null hypothesis when it is false
When you fail to reject the null hypothesis when it should be rejected (failure to reject a false nul
Should not exceed 20%
What is a scatterplot?
Shows relationship of X and Y variables; graphic representation of individual data points
graphical representation of a correlation between two variables
How do you calculate that area under the normal distribution for the 95% confidence interval?
Estimate the standard error of the mean (s divided by square root of N)
then multiply by 1.96 (this is the lower end of the CI)
Explain the rejection region in testing the null hypothesis?
2.5% in upper tail and 2.5% in lower tail
5% left over after calculating the percent of area under the standard normal distribution that falls between the two points
What are the conditions necessary for using an independent samples t test?
have a continuous dependent variable; have a categorical variable as the independent variable. are the means the same when it comes to the dependent variable?
What are the conditions necessary for using a paired samples t test?
What are the conditions necessary for using analysis of variance?
continuous dependent variable
What are the conditions necessary for using a Pearson correlation?
What are the conditions necessary for using a Spearman correlation?
When would you use a grouped frequency distribution?
How do you state the null hypothesis for Pearson correlation?
Ho: O = E (Omicron = Epsilon)
What how does the mean differ from the mode?
mean= Average. Sum of scores divided by the number of scores.
mode= Most frequently occurring variable.
What does a percentile indicate?
The percentage of scores below a given percents.
ex. 25th percentile = 25% of scores below
What information is provided by the z table? (GRAPH)
What is a sampling distribution?
You select many samples from the population→ each sample has a different mean→ the means of the samples form a distribution of numbers
The probability distribution of a given statistic based on a random sample
How do you estimate the variance of a population?
We change the denominator from n to n-1 to get an unbiased estimate
you need to know 1.) Sum of squares (the numerator) and 2.)The degrees of freedom (the n-1 or the denominator) see formula Σf(Χ-χ)²
What is the standard error of the mean?
Standard Deviation of the distribution of sample means
What is the coefficient of determination?
in the neighborhood of multiple regression. the squared correlation coefficient.
*the % of variance the regression model explains*
The square of the correlation coefficient, whose symbol is r2; tells us what proportion of variance in the dependent variable is explained by the independent variable
What is the standard error of the difference?
The standard deviation of the differences between sample means. The standard deviation of a distribution of differences between sample means. The standard deviation of differences between the means of all possible pairs of same-sized samples.
What decision do you make about a null hypothesis if p < .05?
Reject the null hypotheses and conclude that the frequencies in the cells are not distributed in a way that is consistent with the null hypothesis
What are the conditions necessary for using regression? How can it be helpful?
Independence of observations, bivariate normality, homoscedasticity (in the population, the variances in the dependent variable are equal for all values of the independent variable) HELPFUL FOR:
What value of Y would you expect to be related to any value of X? There is no basis for predicting other than the mean of Y. This line would be horizontal intersecting Y at the mean. *The regression line improves the prediction of Y based on any value of X. a Regression line fits data better than a horizontal line. It is better than using the mean of Y as a predicted result of all values of X
What are the conditions necessary for using a chi-square test, and with what kinds of variables?
One categorical variable with two or more kind of variables
What level of measurement would you need for variables in cross-tabulation?
nominal or ordinal
What level of measurement is needed to calculate the mean?
What are outliers?
numbers that stand out as different from the rest. An example might be a list of 1, 4, 7, 10, 29, and 13. 29 would be the outlier because all the rest are numbers you get when you count by 3.an outlier is a number that is an atypical case in a set.
Rare and extreme values in a distribution in a variable
What is the range?
The distance between the highest and lowest numbers
What is the relationship between variance and standard deviation?
the standard deviation is the square root of the variance. or the variance is the square of the standard deviation.
The variance is the square of the standard deviation.
They are measures of variability; they measure how spread out a distribution is
What is kurtosis?
Refers to how high the distribution is. A flat is plataturdic . A tall distribution is leptokurtic.
The degree to which a curve is relatively peaked or flat; depends on the size of a curve’s standard deviation relative to the size of its mean and range
What are transformed or standardized scores? How can they be useful?
Converting scores on a distribution to z scores; can compare scores in different distributions, even if the means and standard deviations of the original distributions are different; transformed to common mean and common deviation
In general what is stated by a null hypothesis?
That there is no difference between expected and actual results.
States there is no difference between the hypothesized variables in the population
When would you use a two-tailed test?
What typical value is set for alpha?
How would you interpret correlation coefficients of -1.00, 0.00, and 1.00?
-1.00 very strong negative correlation. Perfect negative correlation
0.00 no correlations
1.00 very strong positive correlation. perfect positive correlation between 2 variables
As presented by your instructor, what are characteristics of qualitative research?
Important in documenting the specifics of everyday life, behavior in context. Not about numerical data.
What are the characteristics of naturalism?
Objective and unobtrusive observation
What are the characteristics of grounded theory?
Accumulate observations and examine generalization and generate hypothesis. All conclusions are temporary.
Begin with collecting data not by a theory, use data to build your theory
theory evolving out of observations
What are the characteristics of phenomenology?
Focus on structure of experience and consciousness. Not concerned with objects. Interested in the subjective experience.
focus on experiences and what is made of them. exploring the sense that people make out of their lived experiences/reality. different views of people are explored. the meaning behind experiences ex. marriage
What are the characteristics of ethnographic research?
the describing of cultures/ study what cultures are about. cultural anthropologists. Margaret Mead.
For what purposes and when would you use formative evaluation?
To shape and improve an ongoing program. Not used to make crucial decisions. done during the course of the program and how it’s delivered. is everything on track for the program. formative questions are to make things better along the way.
For what purposes and when would you use summative evaluation?
Used to determine the program’s future. Are the program goals achieved? Are the outcomes important?
conducting the evaluation at the end. used to make a decision (should a program be continued or not?) the final decision
For what purposes and when would you use needs assessment?
Done at the beginning of the program. Determines if there is a need for the product/service and to determine who needs the product/service.
What types of variables (levels of measurement) would be used in bar charts, histograms and frequency polygons?
Bar chart: nominal or ordinal
Histogram: interval or ratio
Frequency polygon: interval and ratio
What is stated by β 1 = 0? With what statistical test is it associated?
What is stated by µ1 = µ2? With what statistical test is it associated?
What is stated by u1 = u2 = u3? With what statistical test is it associated?
What is stated by O = E? With what statistical test is it associated?
null hypothesis. Omicron=Epsilon. Chi-square
Null hypothesis: O=E, observed frequencies are equal to expected frequencies. Associated with the Chi Square Goodness of Fit Test
What does a scatterplot look like if the correlation is very weak?
What does a scatterplot look like if the correlation is high and positive?
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