**17.3 Knowledge scores at scale-level**

The item-level responses are summated to scale level and the summary statistics and frequency distribution are supplied in **Table 3** and **Figure 2**.

Based on the summary statistics supplied in **Table 3**, more than one-half of the respondents have knowledge of added sugar in SSBs, with M = 56.02%, SD = 22.03%. The skewness value of −58.20% is similar to its standard error (44.80%) and is thus considered significant. Furthermore, the histogram in **Figure 3** below appears to be approximately normally distributed.


#### **Table 3.**

*Summary statistics of mean knowledge scores (n-278).*

*Knowledge of Sugar in Sugar-Sweetened Beverages in South Africa: A Survey of Postgraduate… DOI: http://dx.doi.org/10.5772/intechopen.106904*

**Figure 3.** *Distribution of knowledge scores (n=278).*

#### **17.4 Hypothesis testing**

The results of the hypotheses tests and t-test are discussed in the section below. Hypothesis:

1.H0: There is no relationship between gender and the knowledge of added sugar in SSBs among the University of Limpopo postgraduate students

H1: There is a relationship between gender and the knowledge of added sugar in SSBs among the University of Limpopo postgraduate students.

2.H0: There is no relationship between BMI and the knowledge of added sugar in SSBs among the University of Limpopo postgraduate students.

H1: There is a relationship between BMI and the knowledge of added sugar in SSBs among the University of Limpopo postgraduate students.

The assumptions of the t-test for independent samples were tested based on visual inspection of the normality of the distribution of mean level of knowledge scores (**Figure 2**) and the 'Levene's test for equality of variance' ([32]: 222). There does not appear to be a significant deviation from normality, based on the figure. Furthermore, homogeneous variances are assumed (F = 0.598, p = .218) using the 5% level of significance. Thus, all assumptions are satisfied.

Based on the results of the study, there is sufficient evidence to say that the level of knowledge of added sugar between male and female University of Limpopo

postgraduate students are different (t (25) = 2.763, p =.011). The mean and standard deviation of male University of Limpopo postgraduate students are M = 46.67 and SD = 21.89, and for females' M = 67.71 and SD = 16.39, indicating a significant difference in the knowledge of sugar between University of Limpopo postgraduate female and male students, using the 5% level of significance. The null hypothesis is rejected, in favour of the hypothesis – there is evidence of the difference between males and females of the knowledge of sugar in SSBs.

Second hypothesis shows that there does not appear to be a significant deviation from normality. Furthermore, homogeneous variances are assumed (F = 0.508, p = .483) using the 5% level of significance. Thus, all assumptions are satisfied.

Based on the results, there is sufficient evidence to say that the level of knowledge of added sugar of male and female University of Limpopo postgraduate students are different (t (22) = −1.228, p = .232). The mean and standard deviation of 'normal weight' University of Limpopo postgraduate students are M = 51.25 and SD = 6.58, and for obese M = 62.50 and SD = 6.15, indicating that the level of knowledge of both 'normal weight' and obese are but not sufficiently different to be significant, using the 5% level of significance. The null hypothesis is not rejected, there is no evidence of the difference between obese and 'normal weight' of the knowledge of sugar in SSBs.
