Question

2. Suppose the National Transportation Safety Board (NTSB) wants to examine the safety of compact cars, midsize cars, and full-size cars. It collects a sample of three for each of the treatments (cars types). Using the hypothetical data provided below, test whether the mean pressure applied to the driver’s head during a crash test is significantly different for each type of car. Use ? = 5% to hand calculate and check your work in SPSS. Compact cars 6,6,7 Midsize cars 4,4,5 Full-size cars 9,8,5

Hypotheses:

Fcrit /threshold:

Source of Variation SS df MS Fobt

Between groups Within groups (error)

Total Conclusion:

Answer 1

H0: There is no significance difference among the mean pressure applied to the driver's head during a crash test for each type of car

H1: There is significance difference among the mean pressure applied to the driver's head during a crash test for each type of car

Let the los be alpha = 5%

From the given data

Cars				Total (Ti)	Ti^2/ni
Campact	6	6	7	19	120.3333
Midsize	4	4	5	13	56.33333
Full Size	9	8	5	22	161.3333
			Total G	54	338

Here P-value = 0.072 > alpha 0.05 so we do not reject H0

Thus we conclude that there is no significance difference among the mean pressure applied to the driver's head during a crash test for each type of car.

SPSS Output:

The manual result and SPSS output results are same