Hypothesis Testing

Dr. Thiyanga S. Talagala
Department of Statistics, Faculty of Applied Sciences
University of Sri Jayewardenepura, Sri Lanka

Which hypothesis test to perform?

in-class explanations

Question 1

In a glaucoma study, intraocular pressure (IOP) values (in mm Hg) were recorded from a sample of 21 elderly subjects. The sample had the following characteristics:

\[n= 21\] \[\bar{x}= 15.2 \text{mm Hg}\] \[s = 3.1 \text{mm Hg}\] At a significance level of 0.05, can we conclude that the mean intraocular pressure of the population differs from 14 mm Hg? Perform a hypothesis test to determine the answer.

Question 2

A market research company conducted a survey to investigate whether the type of beverage ordered with dinner at a restaurant independent of the age of the consumer. A random poll of 240 lunch customers is taken, resulting in the following contingency table of observed values. Can you conclude that the type of beverage ordered is independent of age?

Question 3

A researcher wants to determine whether there is a significant difference in mean intraocular pressure (IOP) among three age groups of elderly subjects. The following data represent the recorded IOP values (in mm Hg) for each group:

Recorded IOP Values (mm Hg) for Each Age Group:

Group 1 (Age 60-65): 14, 15, 13, 16, 15, 14, 17, 16, 13, 15

Group 2 (Age 66-70): 17, 16, 15, 18, 14, 17, 16, 15, 19, 14, 18, 17

Group 3 (Age 71-75): 13, 12, 14, 15, 13, 12, 16, 14, 15, 13, 14

At a 0.05 significance level, can we conclude that the mean intraocular pressure differs among the three age groups?