The given sample is
x = [9.0, 7.3, 6.0, 8.8, 6.8, 8.4, 6.6]
The sample size is n = 7.
From the calculator, obtain
The sample mean is xb = 7.557
The sample std. deviation is s = 1.177
The expected population mean is μ = 6.6
Assume that the weights are normally distributed.
Calculate the z-score test statistic
z = (xb - mu)/(s/√n)
= (7.557 - 6.6)/(1.177/√7)
= 2.15
Select a confidence level of say, 95% so that the α-value if 0.05 for a 2-tailed test.
The null hypothesis is
H₀: xb = μ