37. You are working with the penguins dataset and want to understand the year of data collection for all combinations of species, island, and sex. You write the following code:
penguins %>%
drop_na() %>%
group_by(species) %>%
summarize(min = min(year), max = max(year))
When you run the code in the code box, how many different groups are returned by this code chunk?
- 3
- 10
- 2
- 6
38. You are working with the ToothGrowth dataset. You want to use the glimpse() function to get a quick summary of the dataset. Write the code chunk that will give you this summary.
How many different data types are used for the column data types?
- 2
- 3
- 60
- 1
39. A data analyst is working with a data frame named customers. It has separate columns for area code (area_code) and phone number (phone_num). The analyst wants to combine the two columns into a single column called phone_number, with the area code and phone number separated by a hyphen. What code chunk lets the analyst create the phone_numbercolumn?
- unite(customers, “phone_number”, area_code, sep=”-”)
- unite(customers, “phone_number”, area_code, phone_num, sep=”-”)
- unite(customers, “phone_number”, area_code, phone_num)
- unite(customers, area_code, phone_num, sep=”-”)
40. You are compiling an analysis of the average monthly costs for your company. What summary statistic function should you use to calculate the average?
- mean()
- max()
- cor()
- min()
41. A data analyst is studying weather data. They write the following code chunk:
bias(actual_temp, predicted_temp)
What will this code chunk calculate?
- The average difference between the actual and predicted values
- The maximum difference between the actual and predicted values
- The total average of the values
- The minimum difference between the actual and predicted values
42. A data analyst is working with a large data frame. It contains so many columns that they don’t all fit on the screen at once. The analyst wants a quick list of all of the column names to get a better idea of what is in their data. What function should they use?
- str()
- mutate()
- head()
- colnames()
43. A data analyst is using the unite() function to combine two columns into a single column. What does the sep parameter of the unite() function represent?
- The strings to place between each column
- The vector of columns to join into the final column
- The data frame that is the target of the operation
- The name of the final column formed from the original columns
44. A data analyst is checking a script for one of their peers. They want to learn more about a specific data frame. What function(s) will allow them to see a subset of data values in the data frame? Select all that apply.
- library()
- colnames()
- head()
- str()
45. A data analyst is working with the penguins dataset. The variable island represents the island on which the sample was collected. The analyst wants to create a data frame that excludes records from the island named “Torgersen”. What code chunk will allow them to create this data frame?
- penguins %>% filter(island == “Torgersen”)
- penguins %>% filter(island = “Torgersen”)
- penguins %>% filter(island <> “Torgersen”)
- penguins %>% filter(island != “Torgersen”)
