4. A researcher is interested in comparing tastiness of different kinds of cheese in grilled cheese sandwiches. The researcher expects that Cheddar cheese grilled sandwiches are rated tastier than Swiss cheese grilled sandwiches. This researcher wants to use a within-subjects design. Each participant tastes both Cheddar and Swiss cheese grilled sandwiches. Except for the types of cheese used in the grilled sandwiches, there is no difference between the two kinds of sandwiches. Participants indicate the degree of tastiness on a 10-point scale and the ratings appear in the following table. Tastiness scores tend to be skewed. Participant Cheddar Swiss 1 7 4 2 6 5 3 9 6 4 10 8 5 6 7 6 7 6 7 8 9 a. What statistical test should be used to analyze these data? b. Identify H0 and Ha for this study. c. Conduct the appropriate analysis. d. Should H0 be rejected? What should the researcher conclude?

Participant Cheddar Swiss

1 7 4

2 6 5

3 9 6

4 10 8

5 6 7

6 7 6

7 8 9

Paired t test can be used.

Participant / Cheddar / Swiss
x / y / d=x-y / d^2
1 / 7 / 4 / 3 / 9
2 / 6 / 5 / 1 / 1
3 / 9 / 6 / 3 / 9
4 / 10 / 8 / 2 / 4
5 / 6 / 7 / -1 / 1
6 / 7 / 6 / 1 / 1
7 / 8 / 9 / -1 / 1
totals / 8 / 26

H0: (both sandwiches are equally tasty)

Ha: (Cheddar cheese grilled sandwiches are more tasty)

n =7

Sum of the paired differences =

Sum of squares of the paired differences =

Degrees of freedom = n-1 = 7-1 =6

The p-value is 0.1616

Since the p-value is not less than 0.05, we cannot reject the null hypothesis at 55 level of significance.

The researcher should conclude that both sandwiches are equally tasty.