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

Statistical study: a study that attempts to capture a population’s characteristics by making inferences from a sample’s characteristics; involves hypothesis testing. More comprehensive than a case study.

Stem-and-leaf display: a tree-type frequency distribution for each data value (this one is best understood with an example that is shared later).

Stratified sample: a subset of sampling units from different strata. The population is first divided into non- overlapping subgroups (called strata). Strata are subgroups that are similar (Homogeneous) based upon some characteristic of the group members. Once you have your strata, use simple random samples to select from each subgroup (or stratum). Student t -test: a parametric test to determine the statistical significance between a sample distributionmean and a population parameter; used when the population standard deviation is unknown and the sample standard deviation is used as a proxy.

Student T critical values table : https://people.richland.edu/james/lecture/m170/tbl-t.html

Systematic error: an error that affects all the measurements similarly. An error that results from a bias.

Systematic Sample: For example, 1 in k systematic sampling - This is a procedure that can be used when the population can be sequentially organized. To use it, first choose a starting point at random from the first k individuals. Then choose every kth individual after that. "k" is often selected so that a certain sample size is produced. If N = population, and n = sample size, then k = N ÷ n.

“ t ” distribution: a normal distribution with more tail area than that in a Z normal distribution.

Test statistic: is used in a hypothesis test to help you decide if you will support or reject the null hypothesis (H o ) The test statistic compares differences between observed and expected values.

Thematic Apperception Test: a projective technique in which participants are confronted with a picture and asked to describe how the person in the picture feels and thinks.

Theoretical sampling: a nonprobability sampling process in which conceptual or theoretical categories of participants develop during the interviewing process; additional participants are sought who will challenge emerging patterns. Triangulation: research design that combines several qualitative methods or qualitative with quantitative methods. Can also refer to the use of multiple methods or data sources in qualitative research to develop a comprehensive understanding of the phenomena (Patton, 1999). Also viewed as a strategy to test validity through a convergence of information.

Two-tailed test: a nondirectional test to reject the hypothesis that the sample statistics is either greater than or less than the population parameter.

Type I and Type II errors : A Type I error occurs when the null hypothesis is rejected erroneously when it is in fact true. A Type II error occurs if the null hypothesis is not rejected when it is in fact false.

Unimodal: having exactly ONE mode.

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