A hypothesis regarding the weight of newborn infants at a community hospital is that the mean is 6.6 pounds. a sample of seven infants is randomly selected and their weights at birth are recorded as 9.0, 7.3, 6.0, 8.8, 6.8, 8.4, and 6.6 pounds. the null hypothesis is

Respuesta :

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