Question

Compute the range and sample standard deviation for strength of the concrete (in psi).3910, 4130, 3500, 3200, 2960, 3820, 4130, 4060

Answer 1

The range is the difference between the maximum and minimum value.

The maximum value is 4130 and the minimum is 2960. The range is then: 4130-2960=

A standard deviation of the sample is calculated with this formula:

`s=\sqrt{(1)/(n-1)\sum ^n_(i=1)(x_i-M)^2}`

where n is the sample size, xi is each of the values of the sample and M is the mean of the sample.

First, we have to calculate the mean.

This is done as:

`\begin{gathered} M=(1)/(n)\sum x_i=(1)/(8)(3910+4130+3500+3200+2960+3820+4130+4060) \\ M=(1)/(8)\cdot29710 \\ M=3713.75 \end{gathered}`

Now, we can start calculating the standard deviation.