Homework 7

< CS101

Homework 7 is due 11:59 pm Mon May 26th.

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.

1. Daily Steps problem

Here is the Daily-Steps spreadsheet.

Either file-copy to edit in google docs, or file-download-.xlsx to edit in any other program. For this problem, you do not need to turn in a spreadsheet, just figure out a name and number.

Compute the average number of steps for each person. Question: What is the highest average and who accomplished it? (note these two things for your answer on coursework)

2. Cat Naps Problem

Here is the cat-naps spreadsheet

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 on coursework.

3. Radioactive Banana Problem

Radioactive Banana spreadsheet

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 "baseline" and "banana" columns. Don't select the "seconds" columns, as it's not interesting to graph. Select any chart style other than "area". Unfortunately, area is the default in google docs! 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 for the daily-steps short answer, and 2 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.