Cape Breton University is accessed from Grand Lake Road, which is a busy highway that carries 40 000 cars per day, with a posted speed limit of 80 km/h.

Below are vehicle speeds recorded in km/h by the RCMP in front of CBU during 15 minutes of surveillance - the police want to know if there is a chronic problem with speeding at this location.

60

75

75

75

80

80

80

85

85

100

a) How many observations were reported? Answer

b) Does this data represent a population or a sample? AnswerSamplePopulationNeither

c) How many modes are there? Answer

d) Indicate the mode: (any and all that apply)

80

75

100

none

60

85

Calculate the following:

Mean	Answer
Median	Answer
Range	Answer
Standard Deviation	Answer
Pearson'sSkewness (sk)	Answer
Excel Skewness	Answer

How symmetrically distributed is this data? AnswerApproximately SymmetricalDramatically Negatively SkewedPerfectly SymmeticalDramatically Positively Skewed

Part 2

If order for the police to decide whether or not to be concerned about this data,

they want to develop a 95% confidence interval.

Should at orz distribution be used? Answerz-distributionNeithert-distribution

Calculate the following:

t or z value	Answer
Margin of Error	Answer
Lower limit	Answer
Upper limit	Answer

Based on this confidence interval, is it reasonable to say that the averagedriver:

i) exceeds the speed limit at this location? AnswerInconclusiveNoYes

ii) travels at over 90 km/h at this location? AnswerYesNoInconclusive

iii) might travel at 85km/hat this location?AnswerInconclusiveYesNo

iv) might travel at the speed limit at this location? AnswerInconclusiveYesNo

Part 3

Consider the above to be a pilot study.

If the police now want to conduct a larger study that is more precise (i.e. a higher level of confidence with a smaller margin of error), how large of a sample size do they need?

Calculate the following to complete the table:

Allowable Margin of Error (E)	2 km/h
Level of Confidence	99%
z	Answer
Standard Deviation	Answer
What sample size (n) is required?	Answer