Air pollution (micrograms of particulate per ml of air) was measured along four freeways at each of

Question:

Air pollution (micrograms of particulate per ml of air) was measured along four freeways at each of five different times of day, with the results shown below.
(a) What kind of ANOVA is this (one-factor, two-factor, etc.)?
(b) What is your conclusion about air pollution? Explain, referring either to the F tests or p-values.
(c) Do you think the variances can be assumed equal? Explain your reasoning. Why does it matter?
(d) Perform Hartley's test to test for unequal variances.