Final answer:
There is no effect of the new drug on blood pressure, thus the correct option is A.
Explanation:
The null hypothesis is a statement that assumes there is no significant difference or effect between the variables being studied. In this case, the appropriate null hypothesis would be that there is no effect of the new drug on blood pressure. This means that the new drug does not have any impact on blood pressure levels compared to a control group or a placebo.
To further explain this, we can use a two-tailed t-test to determine if there is a significant difference in blood pressure levels between the experimental group (those who received the new drug) and the control group (those who did not receive the drug). The null hypothesis for this test would be that there is no difference in mean blood pressure levels between the two groups.
To support this null hypothesis, we would need to collect data from both groups and calculate the mean and standard deviation of blood pressure levels before and after treatment. We can then use these values to calculate the t-value and compare it to the critical t-value at a given level of significance. If the calculated t-value is less than the critical t-value, we can accept the null hypothesis and conclude that there is no significant effect of the new drug on blood pressure.
It is important to use the appropriate null hypothesis in a study to ensure that the results are accurate and reliable. In this case, using the null hypothesis that there is no effect of the new drug on blood pressure allows us to properly assess the impact of the drug on this particular variable, thus the correct option is A.