Question

Nist wants to give the buyer of this iron rod a 90% confidence interval for its true conductivity. what is this interval? (round your answers to three decimal places.)

Answer 1

The 6 measurements are 10.1, 10.02, 9.89, 10.05, 10.16, 10.21, and 10.11Mean -10.8333Sample size - 6Standard dev is 0.1Alpha is 1 – 0.90 Z (0.1) = 1.645So the computation would be:Mean ± Z* s/sqrt (n)= 10.0833 ± 1.645*0.1/sqrt(6)= 10.0833± 1.645*0.0408= 10.0833± 0.0672=10.0161, 10.1505 is the interval.90% confident that the iron rod’s true conductivity is between 10.0161 and 10.1504 microsiemens per centimeter.