tailieunhanh - Lecture Statistical techniques in business and economics - Chapter 11: Statistical inference

When you have completed this chapter, you will be able to: Explain the the difference between dependent and independent samples, conduct a test of hypothesis and obtain a confidence interval estimate for the difference between two population means using independent samples and using matched pair sample. | Chapter 11 Statistical Inference: 1. Explain the the difference between dependent and independent samples. 2. Conduct a test of hypothesis and obtain a confidence interval estimate for the difference between Chapter Goals When you have completed this chapter, you will be able to: two population means using matched pair sample. two population proportions. two population means using independent samples. State the null and alternate hypotheses Step 1 Select the level of significance Step 2 Identify the test statistic Step 3 State the decision rule Step 4 Step 5 Hypothesis Testing Do not reject H0 Reject H0 and accept H1 Compute the value of the test statistic and make a decision Recall If both samples contain at least 30 observations we use the z distribution as the test statistic. Comparing Two Populations We wish to know whether the the distribution of the differences in sample means has a mean of 0. Comparing Two Populations The samples are from independent populations. The . | Chapter 11 Statistical Inference: 1. Explain the the difference between dependent and independent samples. 2. Conduct a test of hypothesis and obtain a confidence interval estimate for the difference between Chapter Goals When you have completed this chapter, you will be able to: two population means using matched pair sample. two population proportions. two population means using independent samples. State the null and alternate hypotheses Step 1 Select the level of significance Step 2 Identify the test statistic Step 3 State the decision rule Step 4 Step 5 Hypothesis Testing Do not reject H0 Reject H0 and accept H1 Compute the value of the test statistic and make a decision Recall If both samples contain at least 30 observations we use the z distribution as the test statistic. Comparing Two Populations We wish to know whether the the distribution of the differences in sample means has a mean of 0. Comparing Two Populations The samples are from independent populations. The formula for computing the value of z is: No assumptions about the of the populations are required. shape z 2 2 2 1 n2 s n1 s + = 1 X - 2 X Two colleges are located in York Region. The local paper recently reported that the mean starting salary of a graduate from College 1 is $38,000 with a standard deviation of $6,000 for a sample of 40 graduates. Q uestion The same article reported the mean starting salary of a graduate from College 2 is $35,000 with a standard deviation of $7,000 for a sample of 35 graduates. At the .01 significance level can we conclude the mean salary of College 1 is more? Solve Hypothesis Test State the null and alternate hypotheses Step 1 Select the level of significance Step 2 Identify the test statistic Step 3 State the decision rule Step 4 Compute the test statistic and make a decision Step 5 H0: µ1 = µ2 H1: µ1 > µ2 = Because both samples are more than 30, the test statistic is Z Reject H0 if z > Do not reject the null hypothesis; insufficient .