Question

3.A recent report claims that the monthly sales of a Giant store is less than $2 million due to Corona. A random sample of 30 stores shows that the sample mean is $1.85 million and the standard deviation is $0.38 million. Prove the claim using p-value method at alpha = 0.05.

Answer 1

Below are the null and alternative Hypothesis,
Null Hypothesis, H0: μ = 2
Alternative Hypothesis, Ha: μ < 2

Test statistic,
t = (xbar - mu)/(s/sqrt(n))
t = (1.85 - 2)/(0.38/sqrt(30))
t = -2.162

P-value Approach
P-value = 0.0195
As P-value < 0.05, reject the null hypothesis.