4. In a hospital study, it was found that the standard deviation of the sound levels from 20
randomly selected areas designated as "casualty doors" was 4.1dBA and the standard
deviation of 24 randomly selected areas designated as "operating theaters" was 7.5 dBA.
At alpha=0.05, can you substantiate the claim that there is a difference in the standard
deviations? Use the F Distribution Table H in Appendix A as needed? HINT: See
Example 9-14, pg 532
State the null hypothesis in words?
State the claimed alternative hypothesis in words?
Is this a left-tail, right-tail or two-tailed test?
What is the alpha value to use to select the correct Table H?
What is the numerator degrees of freedom (d.f.N)? NOTE: The numerator is the
"casualty doors".
What is the denominator degrees of freedom (d.f.D)? NOTE: The denominator is the
"operating theater"
WHAT IS THE d.f.N COLUMN TO USE IN TABLE H? NOTE: If between two
columns, use the column with the smaller.
WHAT IS THE d.f.D ROW TO USE IN TABLE H? NOTE: If between two rows, use
the row with the smaller value.
WHAT IS THE CRITICAL VALUE (CV) FROM TABLE H?
What is the numerator standard deviation?
What is the denominator standard deviation?
WHAT IS F?
What is your conclusion?
WHAT IS THE REASON FOR YOUR CONCLUSION?