Project -
Write your answers in the space provided in your own words.
1. Presbycusis is the graduated hearing loss that occurs as a person ages. An estimated one-quarter of Americans between the ages of 65 and 75 and three-quarters of those older than 75 have some degree of hearing loss.
An audiologist is interested in the efficacy of three different types of hearing aids. He gathers three groups of hearing-impaired clients: one group receives analog hearing aids, which convert sound waves into amplified electrical signals. The second group receives digital hearing aids, which use directional microphones to control the flow of sound and convert the sound waves into numerical codes before amplifying them. The third group receives cochlear implants. The results come in, and a statistician conducts an analysis of variance.
a. Determine which is the null and alternate hypothesis by marking an X in the table in the correct box.
|
Research Question
|
Alternative Hypothesis
|
Null Hypothesis
|
|
At least one of the population means is different from another.
|
|
|
|
There is no difference between the population means.
|
|
|
b. In this study what is the hearing aid type considered?
c. What are the treatments (analog hearing aids, digital hearing aids, and cochlear implants) considered?
2. List some of the assumptions underlying the independent-measures ANOVA.
3. What is the difference between repeated-measures and independent-measures designs?
4. Suppose you are interested in studying whether temperature affects spatial reasoning abilities. You decide to test spatial reasoning using completion time scores for the paper-folding test with five people, repeating the test on each person with three different temperatures (40 degrees, 60 degrees, and 80 degrees Fahrenheit).
a. In this experiment, what is the null hypothesis?
b. What is the factor of interest?
c. What is the dependent variable?
5. The results of a two-factor, independent-measures, equal n experiment are summarized in the following matrix. The numerical value in each cell is the mean score obtained from the sample in that treatment condition. Compute the overall means for the scores A1 the scores in A2, the scores in B1, and the scores in B2. Enter each of the means to the right of the appropriate row or below the appropriate column in the matrix.
