Less than and more than totals

You will write functions that build the less than and the more than cumulative frequencies of a table, and one that reads a curve.

The idea. The less than total at the upper limit of a class is the running total. The more than total at the lower limit is $N$ minus the less than total at that limit. A reading at a height is found by straight-line interpolation.

Your tasks.

1. In less_than, return the list of less than totals at the upper limits of the classes.
2. In more_than, return the list of more than totals at the lower limits of the classes. The first entry is $N$.
3. In read_curve, return the horizontal reading, rounded to $4$ decimals, of the less than curve at the height height. The points are given by limits and totals.