A grocery store has an average sales of $8000 per day.The store introduced several advertising campaigns in order to increase sales.To determine whether or not the advertising campaigns have been effective in increasing sales, a sample of 64 days of sales was selected.It was found that the average was $8300 per day.From past information, it is known that the standard deviation of the population is $1200.The p-value is
A) 2.000.
B) .9772.
C) .0228.
D) .5475.

Question

Quizplus · Accepted Answer

We will perform a one-sample t-test since we are comparing the sample mean to the population mean with known population standard deviation.

t = (sample mean - population mean) / (standard deviation / sqrt(sample size))
t = (8300 - 8000) / (1200 / sqrt(64))
t = 3.33

Using a t-table with 63 degrees of freedom (64-1), we find the p-value to be approximately 0.0228. Therefore, we can reject the null hypothesis and conclude that the advertising campaigns have been effective in increasing sales.

A Grocery Store Has an Average Sales of $8000 Per