MATH q10

10. [-l9.61 Points] DEVORESTAT9 5.4.0535. ASK YOUR TEACHER Rockwell hardness of pins of a certain type is known to have a mean value of 50 and a standard deviation of 1.4. (Round your answers to four decimal places.) m use SA (a) If the distribution is normal, what is the probability that the sample mean hardness for a random sample of 11 pins is at least 51? (b) What is the (approximate) probability that the sample mean hardness for a random sample of 36 pins is at least 51? You may need to use the appropriate table in the Appendix of Tables to answer this