Overview
For the following problems identify the type of investigation used (i.e., non-experimental, experimental, or quasi- experimental) and all independent, dependent, and, if any, extraneous variables
- A researcher tested the effect of caffeine on sleep. Forty pilots volunteered to participate in the study and signed up for one of two nights. Pilots on Tuesday night drank a cup of regular coffee and those on Wednesday night received a cup of decaffeinated coffee. They then took a nap and length of time to fall asleep was recorded with the aid of an EEG. Pilots in the caffeine group took significantly longer to fall asleep. The researcher concludes that caffeine interferes with the ability to fall asleep.
- What type of investigation is this?
- What are the variables?
- A researcher wants to determine the effects of seat choice on an airplane to customer satisfaction. For this research, passengers were allowed to sit wherever they wanted to on a two consecutive flights, selecting their seats from among all available.
- What type of investigation is this?
- What are the variables?
- A researcher examines the effects of controlled breaks on reaction times of Air Traffic Controllers. The controllers are randomly assigned to two groups. Group 1 has 20 Controllers that spend 45 minutes on a break in a quiet room, with no talking, TV, or other electronics. Group 2 has 20 Controllers who spend their 45 minutes on a break in a common area break room where people are allowed to talk, watch TV, or use electronic devices. Following the breaks, each Group of controllers returned to their shift where their reaction times were assessed.
- What type of investigation is this?
- What are the variables?
- Information graphics often serve two purposes: helping researchers better understand the data they are analyzing and communicating analytic results to others. Create histograms and frequency tables for the following data set. Forty professional aeronautics students enrolled in an economics course were asked how many hours they had studied during the past weekend. Their responses are provided below.
11 | 23 | 0 | 13 | 5 | 9 | 2 | 1 | 12 | 11 |
7 | 8 | 9 | 10 | 7 | 4 | 6 | 10 | 0 | 7 |
16 | 6 | 15 | 10 | 7 | 3 | 11 | 18 | 2 | 1 |
7 | 3 | 8 | 7 | 3 | 13 | 9 | 8 | 32 | 7 |
For the data above, construct a frequency table and histogram. Evaluate the graphics. Discuss how these graphics helped you assess skew and kurtosis. Is the data normally distributed? If not, is it positively or negatively skewed? Is there kurtosis? If you were presenting these data as frequency tables, what impact would changing the size of the bins have in communicating the results to a non-technical audience?