a) Check the assumptions linearity, homoscedasticity and normality of the
residuals. Is the regression model a reasonable approximation of the data?
From the data in the scatterplot, we can see that the linearity and homoscedasticity
assumptions are met because the residuals are scattered randomly and without forming a
systematic pattern. Therefore, yes, the regression model is a reasonable approximation of
the data.
b) Is there evidence of multicollinearity in the data? (explain)
No, there isn’t any evidence of multicollinearity in the data. This is because the tolerance is
larger than 0.10 and the VIF is smaller than 10.
c) Are there outliers, influential points, or outliers on the predictors? (explain)
There are no outliers as the Std. residual < |3|.
There are no influential points as cook’s distance < 1.
There are no outliers on the predictors as Leverage < 3(2+1)/58 = 0.155.
d) What are the null and the alternative hypothesis to test the regression model?
H0: there isn’t a relation between reading achievement (Y) and language skill (X1) and
perceptual motor skill (X2): r-squared = 0
Ha: language skill (X1) and/or perceptual motor skill (X2) predict reading achievement (Y):
r-squared > 0
e) Can the null hypothesis be rejected? (report test statistic, df, and p value)
Yes, the null hypothesis can be rejected.
F(2,55) = 37,770, p < .005
f) What are the null and the alternative hypothesis to test the individual
coefficients?
H0: βj = 0
Ha: βj ≠ 0
g) Which predictor(s) is/are significant? (report test statistic, df and p values)
Both predictors are significant:
Language skill: T(54) = 4.344, p < 0.05
, Perceptual motor skill: T(54) = 2.998, p < 0.05
h) Write down both the unstandardized and standardized regression equations.
i) Interpret the unstandardized and standardized coefficients (see page 20).
Unstandardized coefficients:
Language skill + 1 ---> increase of the Reading Achievement by 1.049
PercMotorSkill + 1 ---> increase of the Reading Achievement by 0.464
Overall, there is a higher language and perceptual motor skill, meaning a better reading
achievement
Standardized coefficients:
The Language Skill is a better predictor for the Reading Achievement than the Perceptual
Motor Skill.
j) How much variance of Y in total is explained by X1 and X2?
k) How much variance of Y is uniquely explained by X1? How much variance of Y
is uniquely explained by X2? What is the best predictor?
LS = (0.380)^2 x 100% = 14.4%
PMS = (0.262)^2 x 100% = 6.9%
l) Draw a Venn diagram that illustrates the decomposition of the variance of Y
Los beneficios de comprar resúmenes en Stuvia estan en línea:
Garantiza la calidad de los comentarios
Compradores de Stuvia evaluaron más de 700.000 resúmenes. Así estas seguro que compras los mejores documentos!
Compra fácil y rápido
Puedes pagar rápidamente y en una vez con iDeal, tarjeta de crédito o con tu crédito de Stuvia. Sin tener que hacerte miembro.
Enfócate en lo más importante
Tus compañeros escriben los resúmenes. Por eso tienes la seguridad que tienes un resumen actual y confiable.
Así llegas a la conclusión rapidamente!
Preguntas frecuentes
What do I get when I buy this document?
You get a PDF, available immediately after your purchase. The purchased document is accessible anytime, anywhere and indefinitely through your profile.
100% de satisfacción garantizada: ¿Cómo funciona?
Nuestra garantía de satisfacción le asegura que siempre encontrará un documento de estudio a tu medida. Tu rellenas un formulario y nuestro equipo de atención al cliente se encarga del resto.
Who am I buying this summary from?
Stuvia is a marketplace, so you are not buying this document from us, but from seller gaiaantico. Stuvia facilitates payment to the seller.
Will I be stuck with a subscription?
No, you only buy this summary for $4.89. You're not tied to anything after your purchase.