Question

Coffee beans from around the world are used to make coffee. Do coffee tasters prefer coffee beans from particular countries? To investigate this question, a researcher collected coffee aroma ratings based on Arabica coffee beans from two countries, Brazil and Costa Rica. The coffee aroma ratings are summarized in the table below. Each sample contains 10 coffee bean ratings.

	n	Sample Mean	Sample Standard Deviation
Costa Rica	10	7.74	0.26
Brazil	10	7.54	0.25

We will assume that the aroma ratings of coffees from these two countries are normally distributed. Let’s perform a hypothesis test at the 5% significance level. Test that the mean aroma rating of coffee made from Costa Rican coffee beans is greater than the mean aroma rating of coffee made from Brazilian coffee beans.

Let µ₁ be the mean aroma rating of coffee made from Costa Rican coffee beans. And let µ₂ be the mean aroma rating of coffee made from Brazilian coffee beans.

The difference in sample means should be: mean for Costa Rican sample minus mean for Brazilian sample.

What conclusion below is appropriate?

Answer choices:

a) Fail to reject the null hypothesis and conclude that coffee tasters prefer Costa Rican coffee beans over Brazilian coffee beans.

b) Reject the null hypothesis and conclude that coffee tasters prefer Brazilian coffee beans over Costa Rican coffee beans.

c) Reject the null hypothesis and conclude that coffee tasters prefer Costa Rican coffee beans over Brazilian coffee beans.

d) Fail to reject the null hypothesis and conclude that coffee tasters prefer Brazilian coffee beans over Costa Rican coffee beans.

Answer 1

CONCLUSION

Reject the null hypothesis and conclude that coffee tasters prefer Brazilian coffee beans over Costa Rican coffee beans.

Option B