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Thursday 9 March 2017

Definition

      Standard Deviation
Standard deviation is a measure of the dispersion of a set of data from its mean. If the data points are further from the mean, there is higher deviation within the data set. Standard deviation is calculated as the square root of variance by determining the variation between each data point relative to the mean.

Type 1 Error
Type 1 error, known as a “false positive”. The error of rejecting a null hypothesis is when it is actually true. In other words, this is the error of accepting an alternative hypothesis (the real hypothesis of interest) when the result can be attributed to chance. Plainly speaking, it occurs when we are observing a difference when in truth there is none (or more specifically- no statistically significant different).

Alpha
Alpha set the standard for how extreme the data must be before we can reject the null hypothesis. The alpha level is the probability of rejecting the null hypothesis when the null hypothesis is true. Once you have chosen alpha, you were ready to conduct your hypothesis test.

Reliability
Reliability of a scale indicates how free it is from random error. Two frequently used indicators of a scale reliability are test-retest reliability it refer to temporal stability and internal consistency.

Validity
The validity of a scale refers to the degree to which it measure what it is supposed to measure. Unfortunately, there is no one clear-cut indicator of a scale’s validity. The validation of a scale involves the collection of empirical evidence concerning its use. The main types of validity are content validity, criterion validity and construct validity.

Repeated measure
Repeated measure are collected in a longitudinal study in which change over time is assessed. Other (non-repeated measure) studied compare the same measure under two or more different condition.

ANOVA
The one-way analysis of variance (ANOVA) is used to determine whether there are any statistically significant differences between the means of two or more independent (unrelated) groups (although ten to see when are a minimum of three, rather than two groups).

T-test
There are two of different types of t-test available in IBM SPSS that is:
  •  Independent-samples t-test, used when to compare the mean score of two different groups of people or condition.
  •  Paired-sample t-test, used when to compare the mean scores for the same group of people on two different occasions, or when matched pairs.

            Mixed between MANOVA
MANOVA is an extension of analysis of variance for more than one dependent variable. Dependent should be related in some way, or should be some conceptual reason for considering together. Independent variable should consist of two or more nominal or categorical, independent group.

MANOVA
MANOVA test for the difference in two or more vector of means. MANOVA is useful experimental situations where at least some of the independent variable are manipulated.

By - alias su'aidah

References


Book
Pallant, J. (2013). SPSS survival manual: A step by step guide to data analysis using  SPSS (5th ed.). Maidenhead: Open University Press/McGraw-Hill.
Website

http://userwww.sfsu.edu/efc/classes/biol710/manova/MANOVAnewest.pdf

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