A summary of 24 observations of x gave the following information:
∑(x-a)=-73.2 and ∑(x-a)2=2115
The mean of these values of x is 8.95.
(i) Find the value of the constant a.
(ii) Find the standard deviation of these values of x.
HELP PLZ!
A summary of 24 observations of x gave the following information:
∑(x-a)=-73.2 and ∑(x-a)2=2115
The mean of these values of x is 8.95.
(i) Find the value of the constant a.
(ii) Find the standard deviation of these values of x.
HELP PLZ!
Since no probability is given, we denote the mean of x as
We know n is 24, and . Therefore,
Your problem gives
That can be rewritten as .
<------ from above
I'll take a stab at part (ii) as well.
From above, for your second equation, substitute our value of 288 for a, we get
Expanding and simplifying, we get:
<------ remember that from part i
Now, we know that Variance, denoted as
Plugging in our value for and simplifying, we get:
<---- we figured out earlier and
Now calculate standard deviation, denoted as
um... which one is right?
http://www.mathhelpforum.com/math-he...tml#post407749