For the Next Questions, Assume That a Simple Random Sample

Essay

For the next questions, assume that a simple random sample has been taken,
the population standard deviation is not known, and the population is normally
distributed. Medical researchers studying cochlear implants, devices placed behind
the bone in the ear to improve hearing, found the following number of implants
over the last twelve years in children under 3 years old. Use a 90% confidence level
and the following sample data:
-Find the critical value .