What will the following code produce?

A tibble with two rows, showing the mean of value for each group.

What does the argument na.rm = TRUE in functions like mean() and sum() do?

Excludes missing values from the calculation.

What does R-squared measure in a linear regression model?

The % of variance in the outcome explained by the predictors

What is "the fundamental problem of causal inference"?

For any single unit we can observe only ONE potential outcome

Which of the following code snippets subsets the GAPMINDER dataset to countries from Europe?

gapminder %>% filter(country == "Europe")

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Intro to Stats Quiz

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Questions 13

Answers

1
What will the output of the following code be?
"cherry", "date"
FALSE, FALSE, TRUE, TRUE
c(FALSE, FALSE, TRUE, TRUE)
TRUE, TRUE
2
What will the following code produce?
An error, because summarise() cannot handle grouped data.
A tibble with one row containing the overall mean of value.
A tibble with four rows, appending a new column for the mean value.
A tibble with two rows, showing the mean of value for each group.
3
Which of the following programming tools ensures the integration of analysis code & "verbal" interpretation?
RStudio
R
Rmarkdown
Tidyverse
4
Which of the following functions would be key to calculating z-scores?
group_by()
filter()
summarise()
mutate()
5
Given a dataset with a mean of 50 & a standard deviation of 10, what is the Z-score of a data point with a value of 70?
Can't calculate z-score of a single data point.
(50 - 70) / 10 = -2
(70 / 10) * 50 = 35
(70 - 50) / 10 = 2
6
Guess the correlation!
0
0.93
-0.4
0.2
7
In a regression Beta = 0.2.Is it always true that a unit increase in the predictor leads to a 0.2 change in the outcome?
True
False
8
What does the argument na.rm = TRUE in functions like mean() and sum() do?
Removes rows with missing values from the data frame before computation.
Replaces missing values with 0 before computation.
Excludes missing values from the calculation.
Throws an error if missing values are present.
9
What does R-squared measure in a linear regression model?
The total variance in the dependent variable
The % of variance in the outcome explained by the predictors
The correlation coefficient between the dependent and independent variables
The causal effect of the independent variable on the dependent variable.
10
What is "the fundamental problem of causal inference"?
In many cases, conducting an experiment is not feasible or ethical
Correlation is not causation
For any single unit we can observe only ONE potential outcome
R gives error messages that are very hard to understand
11
Which of the following concepts explains why celebrities have "useless" children?
Collider bias
Regression to the mean
Confounding
Randomness
12
Which of the following code snippets subsets the GAPMINDER dataset to countries from Europe?
gapminder %>% group_by(country) %>% summarise(country == "Europe")
gapminder %>% select(country, Europe)
gapminder %>% slice(country == "Europe")
gapminder %>% filter(country == "Europe")
13
Which of the following statements are true?
The median life expectancy in Africa is about 53 years
25% Asian countries have a life expectancy above 75 years
No country in the Americas have a life expectancy above 81 years
All of the above

Intro to Stats Quiz Flashcards | StudBud