Question

making inferences from experiments
this quiz will test your knowledge on making inferences from experiments.
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value: 3
a randomized comparative experiment tests whether a cholesterol medication lowers the overall blood pressure for male patients. the control group has ten male patients and the treatment group, which receives the medication, has 10 male patients. all patients started with a cholesterol level of 245 mg/dl.

	cholesterol in mg/dl
treatment	230	225	220	218	224	240	232	221	235	224

what is the mean of the control group? round to the nearest tenth.
a. 244.9
b. 226.9
c. 235.7
d. 228.3

Explanation:

Step1: Recall mean formula

The mean $\bar{x}=\frac{\sum_{i = 1}^{n}x_{i}}{n}$, where $n$ is the number of data - points and $\sum_{i = 1}^{n}x_{i}$ is the sum of the data - points.

Step2: Identify $n$ and sum for control group

For the control group, $n = 10$. The data points are $241,243,242,245,250,248,246,245,242,247$. The sum $\sum_{i=1}^{10}x_{i}=241 + 243+242+245+250+248+246+245+242+247=2449$.

Step3: Calculate the mean

$\bar{x}=\frac{2449}{10}=244.9$.

Answer:

A. 244.9