Review for the
Final Exam
I.
Below are the times between eruptions of the Old Faithful Geyser, find the mean, median, mode, range,
variance and standard deviation for the data:
98, 92, 95, 87, 96, 90, 65, 92, 95, 93, 98, 94
II.
A city assessor wished to estimate the mean income per household. The previous mean income was
$25,300. A random sample of 12 households in the city showed a mean income of $29,400 and a standard
deviation of $6325.
(a) Find a 95% confidence interval for
μ
, the population mean income per household in the city.
(b) Based on your answer in part (a), would the assessor conclude that the mean income had increased over the
previous estimate of $25,300?
III.
. A study was recently done that emphasized the problem we all face with drinking and driving. Four
hundred accidents that occurred on a Saturday night were analyzed. Two items noted were the number of
vehicles involved and whether alcohol played a role in the accident. The numbers are shown below:
Number of Vehicles Involved
a) What proportion of the accidents involved a single car without the effect of alcohol?
b) What proportion involved No alcohol or a single car?
c) Assuming No alcohol involvement, what proportion of the accidents involved a single car?
d) What proportion of the accidents involved more than a single vehicle?