PSY333 Lecture 2B
What is a normal distribution?
A special type of distribution for continuous scale data.
What type of 2 variable graph do you used when you are looking for difference between groups and your first variable is nominal or ordinal with 2 levels or 3 or more levels and you second variable is scale?
Bar graphs with Error bars Box plot
What are the properties of a normal distribution?
Bell shaped Symmetrical
True or False: Box plots are not very informative
False, They are packed with information
True or false: Graphs can not have multiple categorical variables.
False, They can have various categories
True of False: Box plots do not help you identify extreme outliers.
False, it does indicate extreme outliers
True of false: The shape of distribution may not influence your choice of descriptive statistics and inferential statistics.
False, it does influence our choice of statistics.
True or False: Pie chart can be nominal or scale.
False, pie charts can be nominal only
What does the horizontal y-axis measure for a bar graph?
Frequency counts or percentage.
What are the commonly used graphing methods for displaying 1 variable?
Histogram Simple Bar graph Pie Chart
Why is it important to check for normality?
Normality is a key assumption for many statistical tests other known as parametric tests
What type of graph for 2 variables do you use when you are looking for an association in your design type and the first variable is scale and second variable is scale?
Scatterplot
What are some commonly used methods for displaying 2 variables?
Scatterplot Line Graph Clustered Bar Graph Stacked Bar Graph Stacked % Bar Graph Bar Graph with Error Bars Box Plot
What type of graph for 2 variables do you use when you are looking for an association in your design type and the first and second variable are ordinal?
Stacked % Bar Graph Stacked Bar Graph Clustered Bar Graph
What type of graph for 2 variables do you use when you are looking for an association in your design type and the first variable is nominal and second variable is ordinal?
Stacked % Bar Graph Stacked Bar Graph Clustered Bar Graph
What type of graph for 2 variables do you use when you are looking for an association in your design type and the first and second variable are nominal?
Stacked % Bar graph Stacked Bar graph Clustered Bar Graph
What does the vertical y-axis measure for histograms?
The frequency score
What does the horizontal x-axis measure in a histogram?
The range of scores (possible or actual score)
True of False: Graphs are extremely useful.
True
True of False: Histogram can only be scale measurement.
True
True of False: The standard normal distribution is also known as the standard distribution of scores.
True
True or False: A bell shaped distribution is also called bell curve or gaussian curve.
True
True or False: Bar graphs can be either nominal or ordinal.
True
True or False: Box plots list the median, 1'st and 3'rd quartile, IQR, Minimum and Maximum and outliers.
True
True or False: Boxplots are also known as Box and Whisker plot.
True
True or False: Complex tables are useful for multiple categorical variables.
True
True or False: Graphs used for displaying 2 variables are useful to see the relationship between variables.
True
True or False: IQ score follows a normal distribution.
True
True or False: If observed distribution differs significantly from theoretical normal distribution then it will affect the ability for parametric statistical tests to draw conclusions from the sample data back to the population
True
True or False: If the p<.05 then the assumption off normality has been violated
True
True or False: If the z-score falls outside of -1.96 and 1.96 then the data is significant indicating that skewness and or kurtosis is the cause of the distribution not being normal.
True
True or False: Increasing sample size helps the shape of a normal distribution to become more visible/smoothly shaped?
True
True or False: Normal distributions are common in nature but not universal.
True
True or False: Parametric tests assume the data to be normally distributed so you can't use them if you fail this assumption instead a nonparametric test needs to be used.
True
True or False: Quantiles are sets of values which divide a frequency distribution into equal groups.
True
True or False: The minimum and maximum values of a box plot are also known as whiskers.
True
True or false: Graphs allows you to quickly see how the data is distributed.
True
What are the steps are asses if you have a normal distribution?
You first look at histogram and then you run statistical tests to check for normality.
How do you determine if values for skewness and kurtosis are effects the normality of the distribution?
You look at the z-score
How do you determine if the z-score is not significant?
Z-score is not significant if the values falls between -1.96 and 1.96 (95% of sores)
What does the horizontal x-axis measure for a bar graph?
categories of a variable (ordinal in order from lowest to highest).
What are frequencies?
counting how often every individual value occurs
What is the Kolmogorov-Smirnov (k-S) Test?
dedicated test for normality (data sets > 50)
What is the Shapiro-Wilk Test?
dedicated tests for normality
What are percentages?
ratios of how often every individual value occurs
What are Q-Qplot?
they are plots quantiles of two data sets against each other
What is the z-score equation
z=(skewness or kurtosis)/ Std Error