Hello, I am a Senior from
Florida and I have a really hard general statistics class. I would like
to know if you guys can help me with these two problems
I am having problems with these two questions:
Find the standard deviation of the given data set
 To get the best deal for CD dealer, Jessica called eight
appliance stores and asked the cast of a specific model. The prices
she quoted are listed below.
$300, $203, $272, $332, $440, $119, $129, $254
 Use the binomial probabilty formula to find the indicated
probability. A company finds that an average of 20% of all new employess resign
during the first year. Find the probabilty that among the next 30 employess
hired, exactly five resign during the first year (n=30, x=5,
p=5, = 0.2, q=0.8)


Hi Urial,
Here is a solution to the first problem. There are a
number of equlvalent expressions for the variance V of a data set.
The expression I find most useful is
V = [n times (the sum of the squares of the x's) 
(the sum of the x's squared)] all divided by n times (n1)
You have 8 observations so n = 8.
The sum of the x's is 300 + 203 + ... + 254 = 2049 thus
the sum of the x's squared is 2049^{2} = 4198401
The sum of the squares of the x's is 300^{2} + 203^{2}+
... + 254^{2} = 604335
Hence the variance is
V = (8 * 604335  4198401)/(8*7) = 11362.1
The standard deviation is the square root of the variance and hence
standard deviation = Sqrt(11362.1) = $106.59
Penny

