# Homework 7a

Homework 7 is due 11:59 pm Mon May 29th. This is the first part of it.

As in lecture, you may use any program to edit your spreadsheet -- Google docs or Microsoft Excel, or the free and open source Libre Office application.

## 1. Daily Steps problem

Either file-copy to edit in google docs, or file-download the .xlsx file 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 later on canvas)

## 2. Cat Naps Problem

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 should be multiplied by 2.5 in the total. (Just use = + * to compute the grand total.)

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 Banana Dose. 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 line-style chart of the "baseline" and "banana" columns, but not the "seconds" column. Play around with the appearance of your chart. Move the chart over so it is not covering up the raw data.