Analyzing Characters by Index Researchers often analyze textual data to extract numerical insights. For instance, counting the occurrence of certain words or patterns can reveal trends or correlations. In this step, we’ll analyze characters in the original string vector to answer the following question: Count the number of strings that start with the letter "v". Store this value in a variable x. Count the number of strings that end with the letter "a". Store this value in a variable y. Compute the ratio x/y for this sample. What is the value of x/y? Tips for Working with Strings To solve this problem, keep the following in mind: Extracting Specific Characters: One way to get a specific character is to use substr(). For example, the substring from character 1 to character 1 gives the first character: substr(species_vector, 1, 1) Filtering Vectors: You can filter a vector by adding a condition inside brackets ([]). For instance, the following command selects all elements in species_vector where the first character is "v": species_vector[substr(species_vector, 1, 1) == "v"] Counting Elements in a Vector: To count the number of elements in a vector, you can use sum(). For example: sum(substr(species_vector, 1, 1) == "v") Finding the Last Character: The first character is always at position 1, but the last character depends on the length of the string. You can use nchar() to find the number of characters in a string. For example, the following code returns 9: nchar("virginica") Combining this with substr(), you can extract the last character: substr("virginica", nchar("virginica"), nchar("virginica")) Steps to Solve the Problem Using the tips above, write code to: Count the strings that start with "v" and store this count as x. Count the strings that end with "a" and store this count as y. Calculate the ratio x/y.