Stat 503
Homework #2
(80pts) Due on Thursday 9/10
1. (10pts) The mean and SD of a set of 47 body temperature measurements were as
follows:
y = 36.497 °C
s = 0.172 °C
If the measurements were converted to °F, and the conversion from Celsius to Fahrenheit is
y’ = 1.8 y + 32.
(a)
(5pts) What would be the new mean and SD?
(b)
(5pts) What would be the new coefficient of variation?
2.
(10pts) A researcher measured the average daily gains (in kg/day) of 20 beef cattle; typical
values were
1.39, 1.57,1.44,…
The mean of the data was 1.461 and the standard deviation was .178.
(a)
(5 pts) Express the mean and std in lb/day. ( Hint: 1 kg=2.2 lb)
(b) (5 pts) What is the mean and std after we standardize the data?
3.
(5pts) In a certain population of the freshwater sculpin, Cottus rotheus, the distribution of the
number of tail
vertebra is as shown in the table.
No. of
Vertebrae
Percent of Fish
20
3
21
51
22
40
23
6
Total
100
Find the probability that the number of tail vertebrae in a fish randomly chosen from the
population
(a) (1pt) equals 21
(b) (1pt) is less than or equal to 22
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 Fall '08
 Staff
 Probability, Standard Deviation, Probability theory, Vertebra, Playing card, Fahre nheit

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