Methodology

5.1.1 

Participants: 

There are 96 users participated in the experiments. The number of the users was calculated using the Sample Size Calculator [40]. Here are the formulas used in the Sample Size Calculator:

Sample Size

Where:

Z = Z value (e.g. 1.96 for 95% confidence level), p = percentage picking a choice, expressed as decimal, c = confidence interval, expressed as decimal. By using: Z= 1.96, p = .5, c = .01, the Sample Size = 96.

The following is a brief description about the terms used in the Sample Size Calculator [36]:

1. The confidence interval (also called margin of error): is the plus-or-minus figure usually reported in newspaper or television opinion poll results. For example, if you use a confidence

ss =

Z ² * (p) * (1-p)

c ²

interval of 4 and 47% percent of your sample picks an answer you can be "sure" that if you had asked the question of the entire relevant population between 43% (47-4) and 51% (47+4) would have picked that answer.

2. The confidence level: tells you how sure you can be. It is expressed as a percentage and represents how often the true percentage of the population who would pick an answer lies within the confidence interval. The 95% confidence level means you can be 95% certain; the 99% confidence level means you can be 99% certain. Most researchers use the 95%

confidence level.

When you put the confidence level and the confidence interval together, you can say that you are 95% sure that the true percentage of the population is between 43% and 51%. The wider the confidence interval you are willing to accept, the more certain you can be that the whole population answers would be within that range.

For example, if you asked a sample of 1000 people in a city which brand of cola they preferred, and 60% said Brand A, you can be very certain that between 40 and 80% of all the people in the city actually do prefer that brand, but you cannot be so sure that between 59 and 61% of the people in the city prefer the brand.

3. Percentage: Your accuracy also depends on the percentage of your sample that picks a particular answer. If 99% of your sample said "Yes" and 1% said "No," the chances of error are remote, irrespective of sample size. However, if the percentages are 51% and 49% the chances of error are much greater. It is easier to be sure of extreme answers than of middle-of-the-road ones.

When determining the sample size needed for a given level of accuracy you must use the worst case percentage (50%). You should also use this percentage if you want to determine a general level of accuracy for a sample you already have. To determine the confidence interval

for a specific answer your sample has given, you can use the percentage picking that answer and get a smaller interval.

Participants are group of under graduate and postgraduate students in NCTU and NTHU called

“MSC” who were using mobile phones. These groups of consumers tend to have a good mobile application for serving their needs. Therefore, a total of 96 usable questionnaires were analyzed, the sample consisted of 47 (48.9%) female and 49 (51.1%) male respondents.

5.1.

2 Design and Procedures

The experiments were performed during two months. The first part of the experiment was carried out in the first month. In this part the first version of “EZBuy1: My Product Info” was tested. Nokia N97 mobile phone was used to scan the product barcodes. To get the product information we used an open source database called “USDA National Nutrient Database for Standard Reference Release 18” [41].

The data base was designed by: The National Food and Nutrient Analysis Program (NFNAP) which is a research program that is achieving long-sought improvements in the nutrient values in the National Nutrient Databank System (NDBS). The project, directed by the Nutrient Data Laboratory (NDL), Agricultural Research Service, USDA, It was initiated in 1997 and recently renewed in collaboration with the NIH National Cancer Institute and the Office of Dietary Supplements, and other supporting NIH Offices, Institutes and FDA. The primary outcome of the program will be a body of nutrient data with unprecedented analytical quality. Approximately 5,400 items, representing nearly 60,000 nutrient values, in the USDA National Nutrient Database for Standard Reference (SR) have been either added or updated, using NFNAP generated data. NDL was able to add data on individual carotenoids, vitamin K, α-tocopherol and individual fatty acids, including trans and omega-3 fatty acids to SR.

Following is the procedure of testing our system "EZBuy: My Product Info":

1. Every user created user name and password using the user web page, logged in to the system, created user profile and specified his needs including: culture, allergy type, disease and health case, calories based diet, preferences and dislikes.

2. By using Nokia N97 every user tested J2ME based mobile application side and saw results depends on his needs : First a generated EAN-13 barcodes on the computer was used, then every user got a page contained printed barcodes and finally real products were tested.

3. Every user used the user web page to view history and using other services the system provides as described in previous chapters.

Primary data for this research was collected using a questionnaire designed to serve the purpose of the research objectives. The questionnaire was divided into two sections - the first explores the consumer’s needs and wants from mobile applications and services, their mobile usage preference, and the importance of mobile service applications. The second observes people using the product to discover errors and areas of improvement (usability testing).

Five services that the “EZBuy1: My Product Info” J2ME mobile application provides were measured:

Culture and Food (e.g. Muslims can’t eat pork , vegetarian can’t eat any kind of meat), Allergy assistant (e.g. soy , nuts , milk,…), Food and Diseases , Calories Based Diet , Preferences and Dislikes monitor.

Respondents were required to rate the services from ‘Not important at all’ to ‘Very important’ based on a five-point rating, and write their suggestions.

The second part of the experiments was carried in the second month. In this part the modified version of “EZBuy2: My Product Info” was tested. Participants used new services and rate them.