Question 1192021
standard deviation = 1.36
sample size = 160
sample mean = 49.2
critical z-score at one tail .01 significance level = -2.33.
critical z-score at two tail .01 significance level = -2.58
standard error = 1.36 / sqrt(160) = .1075
z-score = (49.2 - 50) / .1075 = -7.44.
this is way greater than the critical z-score.
the results are significant.
you can conclude that the mean weight of the sample is definitely less than 50 kilograms.