Management homework help

Deliverable 05 – Worksheet

Instructions:  The following worksheet describes two examples – one is an example for independent samples and the other one for dependent samples. Your job is to demonstrate the solution to each scenario by showing how to work through each example in detail. You are expected to explain all of the steps in your own words.

Independent samples:
One of our researchers wishes to determine whether people with high blood pressure can reduce their systolic blood pressure by taking a new drug we have developed. The sample data is shown below, where represents the mean blood pressure of the treatment group and represents the mean for the control group. Use a significance level of 0.01 and the critical value method to test the claim that the drug reduces the blood pressure. We do not know the values of the population standard deviations.

Treatment Group

Control Group

n1

78

n2

70

186.7

201.9

s1

38.5

s2

39.8

1. Write the hypotheses in symbolic form, determine if the test is right-tailed, left-tailed, or two tailed and explain why.

Answer and Explanation

Enter your step-by-step description and explanations here.

This is a lower tailed test because the treatment group has a lower systolic blood pressure compared to the control group.

2. Calculate the critical value and the test statistic.

Answer and Explanation

Enter your step-by-step description and explanations here.

Critical value can be gotten by checking the degree of freedom (70-1= 69) against the level of significance on a t distribution table. Note for a 2 data set like this, we make use of the smaller sample size for the degree of freedom. From the table critical value is 2.382. Since the test is a lower tailed test, critical value will be -2.382

3. Make a decision about the null hypothesis and explain your reasoning, then make a conclusion about the claim in nontechnical terms.

Answer and Explanation

Enter your step-by-step description and explanations here.

Since the t test of -2.3557 is greater than -2.382 which falls in the acceptance region, hence we fail to reject the Null hypothesis. In conclusion there is no enough evidence to prove that the treatment group has a lower systolic blood pressure

Dependent samples

This same new drug was tested on another group, but this time the test was done before the drug was administered, and then tested after the drug was given to the same group. The results are shown in the table below:

Subject

Before

After

Difference

1

199

189

10

2

174

170

4

3

195

177

18

4

171

167

4

5

179

159

20

6

182

151

31

7

193

176

17

8

208

183

25

9

185

159

26

10

155

145

10

11

169

146

23

12

208

177

31

Use the data above with a significance level of 0.05 to test the claim that for the populations of blood pressures before and after the drug, the differences have a mean greater than 0 mm Hg (so the claim is that the drug helps lower the blood pressure). Use the P-Value method to determine whether or not to reject the null hypothesis and state your conclusion.

4. Write the hypotheses in symbolic form, determine if the test is right-tailed, left-tailed, or two tailed and explain why.

Answer and Explanation

Enter your step-by-step description and explanations here.

Where

This is an upper tailed test because from the calculated mean difference value, we have 18.25 which is greater than zero hence making the test upper tailed.

5. Calculate the test statistic and the P-Value.

Answer and Explanation

Enter your step-by-step description and explanations here.

The test statistics is 6.6295.

Pvalue can be obtained by checking the test statistics on a t distribution table relative to the level of significance from the table. Pvalue is 0.00002

6. Make a decision about the null hypothesis and explain your reasoning, then make a conclusion about the claim in nontechnical terms.

Answer and Explanation

Enter your step-by-step description and explanations here.

Since the pvalue (0.00002) is less than the level of significance (0.05), we reject the Null hypothesis.

In conclusion, there is enough evidence to prove that the difference between blood pressures have mean difference greater than zero.