statistics revision for the mock

how to in r studios and what some topics are

how to take a peek at the data

glimpse (what its called)

what function is used to make a box plot and how

tukeyboxplot(y= …., x= ….)

how to make a scatterplot

scatterplot(x=……, y= …. , data = ….)

scatterplot( x = … ,

y= …..,

best_fit_line= TRUE,

data=….)

how do you know what is on the x axis and what is on the y

x= time, catagories and treatment groups. y = mesurements, counts and scores

what is univariate normality

iis each variable normally distributed

how to see wether each variable is normally distributed

is the skewness and kurtosis values between : -2 and +2. skew and kurtosis should be found for both variables

how to find the skew and kurosis

skew_..= …::skew(….),

kurt_…= …::kurtosi(….)

what function is needed for a liner regression model

lm.beta

what does this equation mean

(Y=a+bX). Y= outcome. A = intercept where the line of best fit intercepts the y axis . B= (the slop) The gradiant. positive value for b indicates as X increases the line goes up - negative the opposite x

what is multiple liner regression

when you have two or more predictor variables

what is liner regression

the outcome variable is continuous and mesured on interval or ratio scale

what is the coefficient of determination

R² is the proportion of variation the DEpendent variable that is predictable from the INdependent variable. it can be used to test the hypothesis or prediction of future outcome

what is R² of 0

The model does not explain any of the variation in the dependent variable

R² of 1

the model explains all of the varaition in dependent variable

what are unstandardised coeffients

the original output form the regression analysis. represent the change in the dependent variable for each unit increase in the independent variable

what are standardised coefficients

the underlying data have been standardized so that the variances of dependent and independent variables are equal to 1. Therefore, standardized coefficients are unitless and refer to how many standard deviations a dependent variable will change, per standard deviation increase in the predictor variable.t

what is mediation analysis

it helps to see the relationship between different variables

what are the paths or mediation analysis

a = relationship between predictor and mediator

b = mediator and outcome

c’= direct relationship between predictor and outcome after taking the mediator into account,

c path = total efffect the relationship between x and y while ignoring the mediator