Mohammed Looti - PSYCHOLOGICAL STATISTICS

Learning to Display Percentages on Histograms Using ggplot2

The Challenge of Displaying Relative Frequency in ggplot2 Histograms are fundamental tools in R programming language for visualizing the distribution of data. By default, the popular ggplot2 package calculates and displays the absolute counts (or frequencies) of observations falling into specific bins or categories on the y-axis. While this is useful for understanding raw magnitude, […]

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Understanding and Resolving the “dim(X) must have a positive length” Error in R

Understanding the R Error: dim(X) Must Have a Positive Length Data analysis in R, a powerful statistical programming environment, frequently requires applying functions across rows or columns of complex data structures. However, when utilizing the versatile apply() function, analysts may encounter a fundamental dimensionality issue resulting in the error message: Error in apply(df$var1, 2, mean)

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Calculate Point Estimates in R (With Examples)

In the field of statistics, understanding characteristics of a large group—the population—is often impractical or impossible due to scale. We rely instead on analyzing smaller subsets, known as samples. A point estimate represents a single, calculated value derived from this sample data, serving as our best guess for an unknown population parameter. This process of

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Fix in R: non-numeric argument to binary operator

One error you may encounter in R is: Error in df$var1- df$var2: non-numeric argument to binary operator This error occurs when you attempt to perform some on two vectors and one of the vectors is non-numeric. Examples of binary operations include: Subtraction (–) Addition (+) Multiplication (*) Division (/) This error occurs most often when

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Calculate Expected Value in R (With Examples)

Understanding Probability Distributions and Expected Value A fundamental concept in statistics is the probability distribution, which precisely describes the probabilities associated with all possible outcomes of a random phenomenon. It provides a comprehensive map detailing how likely a random variable is to assume a specific value within a defined range. Understanding this distribution is the

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Calculate Expected Value in Excel

Understanding how to calculate the expected value is fundamental in statistics and decision-making. Before diving into the calculation, we must first define the critical concept of a probability distribution. A probability distribution maps out all possible outcomes of a random variable and assigns a probability to each outcome. It essentially describes the likelihood of a

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Transpose a Data Frame in R (With Examples)

Transposing a data structure is a common operation in data preparation, often required when the orientation of variables and observations is incompatible with the analysis method or visualization tool being used. In the R programming environment, a data frame is the fundamental structure for holding tabular data. Transposing this structure means swapping the rows and

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Remove Specific Elements from Vector in R

Understanding Vectors and the Need for Subsetting In the R programming language, the vector is the most fundamental data structure. It serves as an ordered collection of elements of the same type, whether they are numbers, characters, or logical values. Data manipulation often requires the ability to precisely control the contents of these structures, making

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The Complete Guide: Check MANOVA Assumptions

The MANOVA, or Multivariate Analysis of Variance, is a powerful statistical technique utilized when researchers wish to examine how one or more categorical independent variables (factors) simultaneously influence two or more continuous dependent variables (response variables). Unlike its simpler counterpart, the ANOVA, the MANOVA considers the correlations among the dependent variables, making it a highly

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Add Superscripts & Subscripts to Plots in R

Mastering Text Formatting in R Plots: An Overview Creating high-quality data visualization is essential for effective scientific communication. While R excels at generating powerful graphs, standard text labels often fall short when dealing with mathematical notation, chemical formulas, or statistical terms. To accurately represent variables like $x^3$ or $y_i$, we require specific formatting capabilities, namely

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Author name: Mohammed looti