Research II Statistics
Exercise I
This exercise concerns material in chapter 1 of your text, and the slides that cover that chapter. Handwritten answers are NOT acceptable. You can add notes if we work on it during class, but your work should be largely completed before class, using word processing (that is, not sitting in the hall ten minutes before class scribbling stuff on a piece of paper….). Make as much room as you need typing stuff in.
1. Think of studies you are aware of that might have been reported on the news recently, about health. Give an example in which a study of some type used a sample to make guesses about what would happen in a population. What was the sample? What was the supposed population? What was the study about?
I recently watched a National Geographic documentary called “Stem Cell Universe with Steven Hawking”. It was about some recent breakthroughs in stem cell research. One study that they showed that I found particularly interesting was the scientists turning a dead heart (or ghost heart) into a living heart through the use of the recipients’ stem cells. They took a sample of rats and made stem cells from their skin cells. They then took some ghost hearts from dead rats, which had completely lost their muscle tissue leaving only a shell of sorts, and put the stem cells from the living mice on each heart. They found that the stem cells formed a new, working heart in the ghost heart shell. When transplanted into the mice that the stem cells were taken from, the rats did not reject the heart because it exactly matched their DNA. The sample was the few mice that they did the transplants in and the population would be all lab rats. They were able to use their samples to generalize that this would happen to the entire lab rat population.
2. Give examples of four different variables. For instance, a variable could be eye color. Eyes are what is being measured, and they are being measured for how they vary in color. For each variable name what is being measured, and what sort of variation is being measured.
Gender. Sex is what is being measured, and they are being measured by what the gender they were given at birth.
Grades. Letter grades are what’s being measured, and they are being measured by A, B, C, D, F.
Blood type. Blood is what is being measured, and it is measured for how it varies by type (A, AB, etc.).
Race. Race is what is being measure, and it is measured by how it varies (Black, Caucasian, Hispanic, etc.).
3. Look at the examples of sampling error in the slides. Make up your own example of sampling error. It has to be a new example, it can’t be something from the book or slides. It can follow that format, but has to be a different variable.
The UMass Lowell Psychology Dept. has a lot of research going on right now. In order for these studies to acquire a steady amount of participants, UML has made it a requirement for freshman psychology students to participate in at least two research sessions. Say a professor was doing a study on difference in food preference between males and females; because the studies are all given as options to the students instead of the researchers choosing them, it is possible that the researcher could get a significant amount of one gender over the other. This would be a sampling error.
4. Describe clearly an example of a discrete variable and a continuous variable. Again, these have to be new, not from the slides or the book.
An example of a continuous variable would be listen to music. You could listen to half a song for example or .65ths of a song.
An example of a discrete variable would be winning on a scratch ticket. You either win the full