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STA 2023 . Testing the Difference Between Means (Small Independent Samples). The Two-Sample t-Test for the Difference Between Means. Using the calculator. On the calculator: Press STAT, TESTS, and 4:2-SampTTest Since we have the sample statistics, choose stats and fill in the information.
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STA 2023 Testing the Difference Between Means (Small Independent Samples)
On the calculator: • Press STAT, TESTS, and 4:2-SampTTest • Since we have the sample statistics, choose stats and fill in the information. • Then select your alternate hypothesis. • Then select No to pooled if your variances are not equal or Yes if your variances are equal • Last, select Calculate.
Output: • P-Value = .9971. This is greater that .05 • Answer: At level of significance of 5% there is not enough evidence to reject the claim that the first population mean is less than or equal to the second population mean.
Using Data • Using the raw data for a t-Test is more easy than the z-Test. • We just have to input the data and run the test in the calculator. We do not need the standard deviations. • Example 2: Look at #19 on page 448. • Output: • Answer: There is not enough evidence at the 1% level of significance to support the claim that the new treatment makes a difference in the tensile strength of steel bars.