A cable is made up of four wires. The breaking strength of each wire is a normally distributed random variable with mean 10 kN and standard deviation 1 kN. The strength of the cable, using the brittle wire method, is estimated to be the strength of the weakest wire multiplied by the number of wires.

a) μ =35.858KN

b) median cable strength =36.06KN

Step-by-step explanation:

Let X1, X2, X3, X4 represent the strength of the 4 wires.

We can find the median of the cable strength in minitab as:

Stat - Basic statistics- Display descriptive statistics-variable (C5) -statistics(median) - ok

Median cable strength is 36.06 KN

Therefore the estimate of the mean strength of the cable is 35.858 KN, and the estimate of the median cable strength is 36.06 KN.

the first one is x^2+2x+2

the second one is x^2+4

the last one is x^2-4x+8