Make sure to include the unit of the values whenever appropriate.

Q1 Build a regression model to predict life expectancy using gdp per capita.

Hint: The variables are available in the gapminder data set from the gapminder package. Note that the data set and package both have the same name, gapminder.

Q2 Is the coefficient of gdpPercap statistically significant at 5%?

Hint: Your answer must include a discussion on the p-value.

Yes, the coefficient is statistically significant at 5% because the p value is smaller than 1%

Q3 Interpret the coefficient of gdpPercap.

Hint: Discuss both its sign and magnitude.

The coefficient of gdpPercap is .00076488, meaning as gdpPercap increases by $1, the life expectancy increases by .00076488 years.

Q4 Interpret the Intercept.

Hint: Provide a technical interpretation.

The intercept value is 53.955, meaning if you are born with a $0 gdpPercap, life expectancy has to be 53.95 years

Q5 Build another model that predicts life expectancy using gdpPercap, but also controls for another important variable, year.

Hint: This is a model with two explanatory variables. Insert another code chunk below.

Q6 Which of the two models is better?

Hint: Discuss in terms of both residual standard error and reported adjusted R squared.

The second model is better because there are less errors

Q7 Interpret the coefficient of year.

Hint: Discuss both its sign and magnitude.

The coefficient of year is 17 years, the sign is positive.

Q7.a Based on the second model, what is the predicted life expectancy for a country with gdpPercap of $40,000 a year in 1997.

Hint: We had this discussion in class while watching the video at DataCamp, Correlation and Regression in R. The video is titled as “Interpretation of Regression” in Chapter 4: Interpreting Regression Models.

The predicted life expectancy would be about 76 years

Q8 Hide the messages, but display the code and its results on the webpage.

Hint: Use message, echo and results in the chunk options. Refer to the RMarkdown Reference Guide.

Q9 Display the title and your name correctly at the top of the webpage.

Q10 Use the correct slug.