siteimagine.blogg.se - Describing scatter plots

#DESCRIBING SCATTER PLOTS SERIES#

A series of dots represent the position of observations from the data set. Mathematical language to describe correlation.A Scatterplot is used to display the relationship between two quantitative variables plotted along two axes. Scatterplot matrix or as simple as a 2×2 gridĪlternatively, present one or a number of scatterplot matrices andįacilitate a class or group discussion describing the scatterplots using Students could create their own matrix, it could be 3×3 as in the tree Students are to describe any relationships in theirĬhosen example in terms of dependent and independent variables,Ĭorrelation and comment on any relationships observed. Provide some time for students to explore the matrix before discussingĪsk students (individually or in small groups) to research and locate a

describe the scatter plots in terms of dependent and.

Of scatterplots can be used to display linked variables. Show the dataset trees scatterplot matrix and explain that these group Will consider variables and how they are related in a context that may Relationships that exist between multiple pairs of variables. The task investigates scatterplot matrices, a collection of related (linear/nonlinear, positive/negative, strong/moderate/weak). Variables, correlation and comment on any relationships observed They describe relationships in terms of dependent and independent Using authentic data to make comparisons and draw conclusions. In this activity students consolidate their understanding of scatterplotsĪs they explore the association between two numerical variables The following link, Why Correlation does not Imply Causation in Statistics, may be helpful in explaining the differences. Though this may be the case there may also be other factors that are responsible for the relationship and therefore it cannot be concluded that one variable causes the other. The existence of a relationship does not mean one variable causes the other. It is important for students to understand that causation means that one variable causes the other whereas correlation means that a relationship exists between the variables.

Correlation does not always imply a causal relationship since other factors could contribute.

Note there is a time limit for the use of this Gizmo if you do not have a licence for use. The following Gizmo, Trends in Scatter Plots can be used to show the different trends and strengths in the relationship between two variables.

Students may confuse whether the relationship is positive or negative and may not be able to explain this using the actual variable names.

If they join the points they will create a series of line segments whereas the point of a scatterplot is to be able to fit one line of best fit that can be used for predictions. Ask students to think about why they wouldn’t join the points.

Students may incorrectly joint the points on a scatter plot.

Outliers – are there any data points that appear to be significantly removed from the general pattern?.

Strength – is the relationship weak, moderate or strong?.Direction – is the relationship positive (as the x variable increases, the y variable increases) or negative (as the x variable increases, the y variable decreases)?.Form – is the relationship linear, non-linear or is there no relationship?.When describing the relationship shown in a scatterplot the following features should be considered: For example, does the relationship appear to be linear? If there is a relationship, is it a strong one? When analysing a scatter plot students will look for evidence to indicate there is a relationship or correlation between the two variables.

For example, when analysing an electricity bill what are the two variables? The total cost of the bill (response variable) and the usage (explanatory variable). Provide different scenarios where students are required to identify each variable. When working with scatter plots it is important for students to be able to identify the explanatory (independent) and response (dependent) variables. However, when investigating relationships between two variables, it may not matter which variable is assigned to which axis. The horizontal axis generally represents the explanatory (or independent) variable and the vertical axis generally represents the response (or dependent) variable. Scatterplots are a graphical representation of two sets of numerical data, where each piece of data is often represented using x and y coordinates. At this level, students will use scatterplots to investigate the relationship between two numerical variables.