Sleep Lab

Summary:  You will gather some data about people’s sleeping habits and summarize the data.

Data Collection

Pick 25 adults (18 or older) including yourself, and ask them how many hours they slept last night (to the nearest hour), and their position for going to sleep (back, left side, right side, stomach, or unsure). Record the answers using separate paper or the form below.

Try to do all the data collection the same day. Why do you think it might be bad to collect some data on a Sunday and some data on a Monday?

Need graph paper? Here’s a sheet you can download and print (127 KB PDF).

Data Analysis

General directions:

Show all your work and answers on separate paper; you must show your work for full credit. Whenever possible, use TI calculator commands instead of formulas. Your “work” includes the commands, not the keystrokes.

Do all the graphs on graph paper or in Excel. (If it’s Excel, write down the formula or analysis tool that you used.)

Also hand in your data, either the table above or the separate sheet where you recorded your data. I cannot accept the lab without your raw data. And check your data entry! It’s pretty bad if your answers don’t match your data.

Staple all pages neatly before you come to class; loose sheets and insecure fasteners cost a 10% penalty.

Question 1 (points: 3):  Obviously you took a convenience sample. If this was a real-world statistical study, describe how you would obtain a proper sample and name that type of sample.

The next two apply to your data for sleeping position.

Question 2 (points: 2):  What is the type of the data? (Give the most specific answer, not just “numeric”, “attribute”, “qualitative”, or “quantitative”.)

Question 3 (points: 5):  Out of bar graph, pie chart, histogram, and stem-and-leaf, construct the most appropriate graph for this data set. Include any necessary labels or scaling.

The rest of the questions apply to your data for hours slept.

Question 4 (points: 2):  What is the type of the data? (Give the most specific answer, not just “numeric”, “attribute”, “qualitative”, or “quantitative”.)

Question 5 (points: 5):  Out of bar graph, pie chart, histogram, and stem-and-leaf, construct the most appropriate graph for this data set. Include any necessary labels or scaling.

Question 6 (points: 1):  What is the shape of this data set? (It might not match any of the shapes we studied. If that’s the case, say so.)

Question 7 (points: 3):  Compute the mean and s.d. of this data set. Report them with their symbols, rounding to one decimal place.

Question 8 (points: 2):  Compute and report the five-number summary.

Question 9 (points: 3): On graph paper, draw a modified boxplot. Include any outliers, and show and label the axis. (You can use your TI to help you.)

Question 10 (points: 2):  What’s your raw score? (How many hours did you sleep?) Give your percentile rank and show how you computed it.

Question 11 (points: 2):  Find your own z-score in this data set, rounded to two decimals. Beware of The Big No-no!