2.E: Exercises

Exercises – Ch. 2

1. In your own words, describe why we study statistics.
2. For each of the following, determine if the variable is continuous or discrete:
   1. Time taken to read a book chapter
   2. Favorite food
   3. Cognitive ability
   4. Temperature
   5. Letter grade received in a class
3. For each of the following, determine the level of measurement:
   1. T-shirt size
   2. Time taken to run 100 meter race
   3. First, second, and third place in 100 meter race
   4. Birthplace
   5. Temperature in Celsius
4. What is the difference between a population and a sample? Which is described by a parameter and which is described by a statistic?
5. What is sampling bias? What is sampling error?
6. What is the difference between a simple random sample and a stratified random sample?
7. What are the two key characteristics of a true experimental design?
8. When would we use a quasi-experimental design?
9. Use the following dataset for the computations below:

   X	Y
   1	1
   2	3
   5	5
   7	1

   Computations to use for the above data set:

   1. ΣX
   2. ΣY²
   3. ΣXY
   4. (ΣY)²
10. What are the most common measures of central tendency and spread?

Answers to Odd-Numbered Exercises – Ch. 2 - Highlight to reveal them

1. Your answer could take many forms but should include information about objectively interpreting information and/or communicating results and research conclusions
2. For each of the following, determine the level of measurement:
   1. Ordinal
   2. Ratio
   3. Ordinal
   4. Nominal
   5. Interval
3. Sampling bias is the difference in demographic characteristics between a sample and the population it should represent. Sampling error is the difference between a population parameter and sample statistic that is caused by random chance due to sampling bias.
4. Random assignment to treatment conditions and manipulation of the independent variable
5. Use the following dataset for the computations below:
   1. 15
   2. 36
   3. 39
   4. 100