Compute the test statistic t

Question

Medical literature tells us that our blood is mainly composed of red and white corpuscles and a normal human body must average 7250/mm³ of white blood cell counts. If a sample of 15 individuals chosen at random from a certain place has an average of 4850/mm³  with a standard deviation of 2500/mm³, would you say that the people in that place have low white blood cell counts?

Compute the test statistic t

Answer 1

7250 = mean

4850-7250 = -2400

2400/2500 = 24/25 = 0.96

.96/sqr15 = .2479 = z score

with a 95% confidence interval or as low as 20% confidence interval

the people in that place do not have a low white blood cell count