Answer:
Step-by-step explanation:
If half of the wine barrels are infected, it means that the proportion of infected wine is 0.5
We would set up the hypothesis test.
For the null hypothesis,
p = 0.5
For the alternative hypothesis,
p < 0.5
Considering the population proportion, probability of success, p = 0.5
q = probability of failure = 1 - p
q = 1 - 0.5 = 0.5
Considering the sample,
Sample proportion, P = x/n
Where
x = number of success = 28
n = number of samples = 80
P = 28/80 = 0.35
We would determine the test statistic which is the z score
z = (P - p)/√pq/n
z = (0.35 - 0.5)/√(0.5 × 0.5)/80 = - 2.68
From the normal distribution table, the area below the test z score in the left tail 0.0037
Therefore,
p value = 0.0037
Assuming a significance level of 0.05, therefore,
Since alpha, 0.05 > than the p value, 0.0037, then we would reject the null hypothesis.
