Please explain how to set up and solve. I have attempted to answer, please let me know if right or wrong...
A sample of n= 36 scores is selected form a population with o= 12. if the sample mean of M=56 produces a z score of z= +3.00 then what is the population mean?
*52 (is this correct?)
A sample of n= 9 scores is obtained from a population with u= 70 and o= 18. if the sample mean is M=76, what is the z-score for the sample mean?
* z= 0.50
*z= 0.33 ( is this correct?)
* z= 3.00
A random sample of n=4 scores is obtained from a normal population with u= 30 and o= 8. what is the probability that the sample mean will be smaller than M= 22?
* 0.1587 ( is this correct?)
a random sample of n= 9 scores is obtained from a normal population with u= 40 and o= 18. what is the probability that the sample mean will be greater than M= 43?
*0.4325 ( is this correct?)
=> M-u = z*o/sqrt(n)
=> 56 - u = 3*12/sqrt(36)
=> u = 56 - 3*12/6 = 50
z = ...
A few problem related to sample and population mean are solved here.