Modern software applications require rapid data access capabilities. An experiment was conducted to test the effect of data file size on the ability to access the files (as measured by read time, in milliseconds). Three different levels of data file size were considered: small-50,000 characters; medium-75,000 characters; large-100,000 characters. A sample of eight files of each size was evaluated. Go to the Resources section in this syllabus and open the file access.xls. This file contains access read times in milliseconds.
1. Is there evidence of a significant difference in the variance of the access read times for the three file sizes? Test at the 95% confidence level.
2. At the 5% level of significance, is there evidence of a difference among the mean access read times for the three file sizes?
3. If appropriate, use the Tukey-Kramer multiple comparisons procedure to determine which file sizes significantly differ with respect to mean access read time. Test at the 95% confidence level.
4. Specifically, what conclusions can you reach?
Small Medium Large
2.05 2.24 2.08
2.04 2.21 2.34
2.21 2.23 2.33
2.12 2.09 2.24
2.32 2.52 2.71
2.31 2.62 2.73
2.48 2.57 2.9
2.42 2.61 2.72