形 kata

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by Matt Hall

You have a 'log', a series of bulk density measurements from a borehole. There is a measurement every 0.1524 m, starting at the top of the borehole. The measurements have units of kg/m³ and look like this:

The log contains a number of geological 'beds' which have a very specific definition: neighbouring pairs of samples that differ by more than 100 kg/m³ constitute a bed boundary. These are bed boundaries. Any section of the log between two bed boundaries is a bed. If the boundaries are 5 samples apart, assume the bed is 5 × 0.1524 = 0.7620 m thick.

Answer the following questions about your data.

1. How many samples are in your dataset?
2. Calculate the mean μ and standard deviation σ of the data. How many samples are greater than (μ + σ)?
3. How many beds are there? Include the first and last beds (those at the very top and bottom of the log).
4. How many beds are thicker than 10 m?

Example

For the short example data above, the questions would be answered as follows:

1. There are 12 samples in the dataset.
2. μ is 2394.4 and σ is 340.74, so 5 samples are greater than (μ + σ).
3. There are 3 beds in the data, with densities of about 2200, 2800, and 2000 kg/m³ respectively.
4. The bed thicknesses are 0.4572, 0.7620, and 0.6096 m respectively, so 0 of these beds are thicker than 10 m.