Question

1. A program to decrease littering was carried out in four cities in California’s Central Valley starting in August 2011. The amount of litter in the streets (average pounds of litter collected per block per day) was measured during July before the program started and then the next July, after the program had been in effect for a year. The results were as follows:

City	July 2011	July 2012
Fresno	9	2
Merced	10	3
Bakersfield	8	9
Stockton	9	1

Use the 5 steps of hypothesis-testing and a .01 significance level to determine whether the program was successful in decreasing litter. Show your work!!!!

           

1. State your hypotheses.

2. Determine the characteristics of the comparison distribution.

3. Determine the cut-off value for a 1% significance level.

4. Determine the observed t score.

5. Decide whether or not to reject the null and give a verbal explanation.

6. Compute the effect size and determine whether it is small, medium, or large.

Compute the power of the test. How many subjects are needed for a power of .80 given your effect size?

Answer 1