Factor 2x^3 - 3x^2 + 2
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Answer:
The average hold time is 10.47 minutes.
Step-by-step explanation:
Let <em>X</em> = time the customers of a phone-in technical support business spend on hold.
The population mean of the random variable <em>X</em> is, <em>μ</em> = 11 minutes.
The population standard deviation of the random variable <em>X</em> is, <em>σ </em>= 1.16 minutes.
A random sample size, <em>n</em> = 62 callers are selected.
According to the Central limit theorem if large samples (<em>n</em> > 30) are selected from an unknown population with mean <em>μ</em> and standard deviation <em>σ</em> then the sampling distribution of sample mean () follows a Normal distribution.
The mean of the sampling distribution of sample mean is:
The standard deviation of the sampling distribution of sample mean is:
It is provided that .
Compute the value of <em>a</em> as follows:
The value of <em>z</em> for the above probability is, <em>z</em> = -0.806.
The value of <em>a</em> is:
Thus, the average hold time is 10.47 minutes.