2022 Introduction to Statistics in Research Mitchell 2nd ed

I N T R O T O R E S E A R C H : D A T A V I S U A L I Z A T I O N & C O M M O N S T A T T E S T S

Sample Size: the number of elements in a sample from a population.

Scatterplot: a way to visualize bivariate data. A scatterplot plots pairs of measurements for the x and y-axis that depict both the direction and the shape of a relationship between the two variables. For example, this scatterplot shows a positive correlation. (Quiz)

Table 37: A scatterplot showing a positive correlation

Selection bias: a term to describe where unconscious prejudices can bias the selection of a sample. For example, convenience sampling.

Significance: the significance level of a hypothesis test is the change that the test erroneously rejects the null hypothesis when the null hypothesis is true.

Simple Random Sample: A sample size "n" is selected from the population in a way that ensures that every different possible sample of the desired size has the same chance of being selected.

Simpson's Paradox: what is true for the parts is not necessarily true for the whole (see confounding).

Skewed Distribution: a distribution that is not symmetrical. Skewness measures the asymmetry of the distribution.

Snowball sampling: a nonprobability sampling procedure in which subsequent participants are referred by current sample elements; referrals may have characteristics, experiences, or attitudes similar to or different from those of the original sample element – a common technique for qualitative methodologies.

Sommer’s d : a measure of association for ordinal data. Compensates for “tied” ranks. Adjusts for the direction of the independent variable.

Spearman’s rho: correlates rank between two ordered variables; an ordinal measure of association.

Standard Deviation (SD): Standard deviation tells you how data values vary around the mean. A larger standard deviation means there's more variability in your data while a smaller deviation means there's less variability.

Above the line is called the sum of squared deviations.

Below the line is sample size - 1

Equation 1: Standard deviation equation

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