Homework 2 Answers

BSTA 512/612

Answers are not necessarily complete! This is just meant to serve as a check if you are stuck.

Questions

Question 1

Part a

Answer:

Part b

Answer:

term	estimate	std.error	statistic	p.value
(Intercept)	1.2819	0.7196	1.7814	0.0753
Fatalism	0.2458	0.0395	6.2273	0.0000

Part c

Answer:

Part d

Answer:

term	estimate	std.error	statistic	p.value
(Intercept)	5.4599	0.2087	26.1594	0.0000
FatalismC	0.2458	0.0395	6.2273	0.0000

Part e

Answer:

Question 2

Attaching package: 'palmerpenguins'

The following objects are masked from 'package:datasets':

    penguins, penguins_raw

Part a

# A tibble: 3 × 2
  species   flipper_ave
  <fct>           <dbl>
1 Adelie           190.
2 Chinstrap        196.
3 Gentoo           217.

Part b

Warning: Removed 2 rows containing non-finite outside the scale range
(`stat_summary()`).

Warning: Removed 2 rows containing missing values or values outside the scale range
(`geom_point()`).

Part c

Write out the fitted regression equation that models the flipper length by penguin species. Use LaTeX math markup or insert an image of your equation. Do not yet insert values for the regression coefficients, i.e. use the generic coefficients \(\widehat{\beta}_0, \widehat{\beta}_1\). Use Adelie as the reference level.

Part d

term	estimate	std.error	statistic	p.value	conf.low	conf.high
(Intercept)	189.953642	0.5404799	351.453643	0.000000e+00	188.890526	191.016759
speciesChinstrap	5.869887	0.9699452	6.051772	3.794027e-09	3.962018	7.777756
speciesGentoo	27.233349	0.8066819	33.759714	1.844813e-110	25.646617	28.820082

Part e

How do we interpret each of the regression coefficients for this model? Write out a separate interpretation for each of the coefficients.

Part f

Calculate the mean flipper length (and the 95% CI) of penguins in the Chinstrap and Gentoo species using the predict() function.

Chinstrap penguins: 195.82 mm