Answer:
-0.880
Step-by-step explanation:
Mean X = 56.7
Sd = 30
N = sample size = 64
Null hypothesis:
H0:u = 60
Alternative hypothesis:
H1:u not equal to 60
This corresponds to a 2 tailed test. So we will have to use a z test with 1 mean, known population and standard deviation
Level of significance = 0.05
Z critical value = 1.96
The test statistic
Z = X - u/sd/√n
= 56.7 - 60/30√64
= -0.880
The test statistic is equal to -0.880