(iv) Based on your answers in parts (i)-(ii), will you reject or fail to reject the null hypothesis? Are the data statistically significant at level a? O At the a = 0.05 level, we reject the null hypothesis and conclude the data are not statistically significant. O At the a = 0.05 level, we reject the null hypothesis and conclude the data are statistically significant. O At the a = 0.05 level, we fail to reject the null hypothesis and conclude the data are not statistically significant. O At the a = 0.05 level, we fail to reject the null hypothesis and conclude the data are statistically significant. (v) Interpret your conclusion in the context of the application. O Fail to reject the null hypothesis, there is sufficient evidence that there is a difference in mean vocabulary scores between the control and experimental groups. O Reject the null hypothesis, there is sufficient evidence that there is a difference in mean vocabulary scores between the control and experimental groups. Reject the null hypothesis, there is insufficient evidence that there is a difference in mean vocabulary scores between the control and experimental groups. O Fail to reject the null hypothesis, there is insufficient evidence that there is a difference in mean vocabulary scores between the control and experimental groups. (b) Find a 95% confidence interval for 4, - 42. (Round your answers to two decimal places.) lower limit upper limit Explain the meaning of the confidence interval in the context of the problem. O Because the interval contains only positive numbers, this indicates that at the 95% confidence level, the population mean score for the experimental group is higher than for the control group. O Because the interval contains both positive and negative numbers, this indicates that at the 95% confidence level, we cannot say that the population mean scores are different before any instruction began. O Because the interval contains both positive and negative numbers, this indicates that at the 95% confidence level, the population mean score for the experimental group is higher than for the control group. O Because the interval contains only negative numbers, this indicates that at the 95% confidence level, the population mean score for the experimental group is lower than for the control group.