WEEK 9 quantitative data analysis

what is quantitative analysis?

explaining observations through numerical representations by assigning numerical codes to answers

what is quantification?

converting data into a numerical format

what does quantification allow data to do?

allows data to be recorded on a computer that a computer can analyze

what does quantification require?

a codebook

what is coding data?

coding or assigning numbers to information

do many coding schemes already exist?

yes

what is an example of coding data?

gender

1=men 2=women

job security

0=not secure 1=somewhat secure 2=secure 3=very secure

what is a codebook?

the document used in data analysis that tells the location of different items in the data file

what is an example of a codebook

a codename for the question "what province are you from" would be G7.

if you didnt search for the code, numbers would show up, like 1-10.

when you search G7, the question will show up as well as what each number represents

1=nova scotia

2=ontario

3=quebec

4=alberta

what happens when people answer with "dont know" or "refuse to answer"?

these responses will show up as its own number as well

what are the 2 essential functions of a codebook

1. is a primary guide in the coding process

2. is the guide for locating variables and interpreting codes

what is data cleaning?

the process of detecting and correcting coding errors in a data set

what is an example of data cleaning

if you search a code that shows gender and 1=man, 2=women and 3=no answer, if the number 7 shows up it is an error and needs to be fixed

what is contingency cleaning?

checking that only the cases that should have data entered have such data

what is an example of contingency cleaning

if someone answers 1=man to one question and 1=being a mother, these dont align and need to be cleaned

what is univariate analysis?

the examination of the distribution of cases of only one variable

- descriptive in nature

what is the simplest form of analysis?

univariate analysis

what 3 things does univariate analyses include?

1. frequencies

2. averages

3. measures of dispersion

what are frequency distributions?

the number of times a variable is observed in a sample

100 white people, 200 asian, 50 black

how do you find the frequency distribution for nominal variables?

divide the frequency of a category by total responses

100 white people in a sample, 200 asian, 50 black.

100 / 350 = .29 frequency for white people

what is a cumulative percentage?

the frequency of the category after adding all other categories before it. always equals to 1

what is a valid percentage?

the frequency distribution after taking into account people who responded "don't know" or "refuse to answer"

when are pie charts used?

for nominal variables with very few categories

- not for ordinal variables

what are the 3 measures of central tendency?

mean median mode

what do the measures of central tendency show?

typical or central value of observations

why do the 3 measures of central tendency often give different values?

because the mean is affected by outliers

what is the mean?

the average, adding all values and dividing by number of values

what is the median?

the centre value after rank-ordering the responses

- the better measure

what is the mode?

the most frequent value

what are measures of dispersion?

the distribution of values around a central value (mean,median,mode)

what are the measures of dispersion also called?

measures of variability

what are the 2 measures of dispersion?

1. range

2. standard deviation

what is the range?

the difference between the highest and lowest values by subtracting the highest from lowest value

what is the standard deviation?

the average deviation from the mean, where things fall around the mean

what is a deviation score?

the distance from the mean for a particular observation

what do larger standard deviations and lower standard deviations look like?

larger = a bigger dispersion around the mean

lower = higher point, lower dispersion

what is a bivariate analysis?

analysis of 2 variables at the same time to see their relationship with one another

what is cross-tabulation?

a form of presenting bivariate analyses

how do we construct/read bivariate tabels?

by seeing how the value of the dependent variable depends on the value of the independent variable

what is a multivariate analysis?

the analysis of 3 or more variables that influence one another

- more than 1 independent variable

what is an example of a multivariate analysis?

seeing how age and gender are related to health quality