Size Estimates By Name Loop (Loops)

This is a followup to Size Estimates by Name.

Download and import data on dinosaur lengths with species names.

Write a function mass_from_length() that uses the equation mass <- a * length^b to estimate the size of a dinosaur from its length. This function should take two arguments, length and species. For each of the following inputs for species, use the given values of a and b for the calculation:

For Stegosauria: a = 10.95 and b = 2.64 (Seebacher 2001).
For Theropoda: a = 0.73 and b = 3.63 (Seebacher 2001).
For Sauropoda: a = 214.44 and b = 1.46 (Seebacher 2001).
For any other value of species: a = 25.37 and b = 2.49.

Use this function and a for loop to calculate the estimated mass for each dinosaur, store the masses in a vector, and after all of the calculations are complete show the first few items in the vector using head().
Add the results in the vector back to the original data frame. Show the first few rows of the data frame using head().
Calculate the mean mass for each species using dplyr.

Expected outputs for Size Estimates By Name Loop: 1