A random sample of n = 49 scores is selected from a normal population with a mean of = 80. After a treatment is administered to the individuals in...

A random sample of n = 49 scores is selected from a normal population with a mean of μ = 80. After a treatment is administered to the individuals in the sample the sample mean is found to be M = 75. If the population standard deviation is σ = 30, is the sample mean sufficient to conclude that the treatment has a significant effect? Use a one-tailed test with α = 0.05. Can you show me how it is done please?