The Lengths of Steel Rods Produced by a Shearing Process

The lengths of steel rods produced by a shearing process are normally distributed.A random sample of 10 rods is selected; the sample mean length is 119.05 centimetres; and the sample standard deviation is 0.10 centimetres.The 90% confidence interval for the population mean rod length is ___.

A) 118.99 to 119.11
B) 118.87 to 119.23
C) 119.00 to 119.10
D) 118.89 to 119.21
E) 119.21 to 123.87