Homework 7

< CS101

Homework 7 is due 11:59 pm Wed May 29th. This is the last homework! There are some short-answer questions on networking and 2 spreadsheet problems.

As in lecture, to edit your spreadsheet for free, you may use Google docs or Microsoft skydive in the browser, or the free LibreOffice application. All spreadsheets are distributed in ".xlsx" format.

The first problem is just the short-answer questions below. Just type your answers into the text area below, after each :

There is no Run button and no saving provided for this homework. Save copy of your answer text temporarily to paste in to coursework once you've completed everything.

As usual, at the very top of your pasted in text, add any additional notes for the grader. In particular, the name of the partners if done as a team. For work done as a team, only one person should submit the homework.

1. Short Answer

2. Cat Naps Problem

Get cat-naps.xlsx in docs (make a copy) or download cat-naps.xlsx to get started.

This file includes some data on different cats and how many naps they take per day.

1. Use sum() to compute the total naps for each group of cats (three separate totals)

2. At the bottom of the spreadsheet, (B32) compute a grand total of all the naps, except the silly cat naps count double. (Just use = + * to compute the grand total.)

Download your cat-naps.xlsx so you can turn it in later.

3. Radioactive Banana Problem

In docs or download radioactive-banana.xlsx. as above, prepare it for editing.

This file includes 2 columns of real raw "count" data from a geiger counter. The geiger counter counts flashes of ionizing radiation, some number of counts every 30 seconds. The "baseline" column shows the counts every 30 seconds just sitting in my office. These counts are from just normal background radiation that exists everywhere on earth. The "banana" column shows the counts with a banana sitting on top of the geiger counter. Bananas are slightly radioactive (though totally safe!) because they contain potassium, and 0.0117% of natural potassium is the radioactive isotope potassium-40 which has a half life of 1.25 billion years. About 15 of these atoms per second in the banana will disintegrate giving off a tiny bit of radiation, and this can be measured. See Wikipedia. Note: if you eat a lot of bananas, you just excrete the potassium to maintain a normal level, so don't worry about it! Indeed, potassium is critical for life.

1. Use sum() to compute the total counts for the baseline and banana columns. Remember to use the Fill Right command.

2. Below the total counts, compute the counts-per-minute for the baseline and banana data. You can use Fill Right again. You can use the number 990 (the number of seconds measured here) directly in your formula. The CPM should be between 10 and 20. Note that the CPM for the banana data is a little higher than the baseline CPM -- science! (optional) Use Format > Number to set the cpm to just use 2 decimal places so it looks better.

3. Make a chart of the raw data (not the computed numbers). Select the "Use Column A as Labels" chart option, to it uses the "seconds" data for the X-axis. Select any chart style other than "area". Unfortunately, area is the default in google docs! I recommend clicking More and then using line chart. Play around with the appearance of your chart. Move the chart over so it is not covering up the raw data.

4. When everything is done, download radioactive-banana.xlsx so you can turn it in.

Turn In

Go to CourseWork as usual. There are three question: one question to paste in your short-answers, and two questions to upload your .xlsx files. Be careful to upload your edited .xlsx files, not the original starter files that just have the data in them.