Statistical Difference in Two Sample Means

Related BrainMass Solutions

• Differences between Statistical and Practical Significance

  What is the difference between these two concepts? How does a researcher explain the difference to a manager? Can the size of a sample affect the difference between statistical and practical significance? If so, explain how.

• Thesis

  (I gave a pre and post test) Ho: µ1 - µ2 = 0, or Md=0
  H1: µ1 - µ2 <> 0 or Md<>0
  where Md is the difference between sample means, µ1 - µ2 is the difference between population means specified by the null hypothesis (usually zero), and

• Hypothesis Testing - Compute the statistical test using the z

  Limit= (x2-x1)+z x standard error = 0+1.7507*1.16 = 2.03 (x2-x1)=0 since the hypothesized difference between the two means is zero Lower Limit= (x2-x1) - z x standard error = 0-1.7507*1.16 = -2.03 The observed difference between the two

• Statistical Analysis on Dyes

  Use sample means to answer this question. Is the difference between the two sample means statistically significant? Can you tell from just the P-value whether the difference is large enough to be important in practice?

• Important information about Test Statistic, P-value

  2) When the necessary conditions are met a two-tail test is being conducted to test the difference between two populations means but your statistical software provides only a one-tail area of 0.036 as part of its output.

• Discussing Statistical Significance

  Statistical significance in the field of statistics "means that the difference is likely greater than we would expect due to sampling error" (McDaniel & Gates, 2011, p. 528).

• Statistical Power - Size

  In its simplest form, an effect size is the difference between two means divided by the pooled standard deviation for those means (this particular type of effect size analysis is frequently referred to as Cohen's d), thus: Where: SD = Standard Deviation

• Power Analysis and type of quantitative test

  To test if they are different, use the independent two-sample t-test with unequal sample sizes and unknown variances (this is also sometimes called the Difference of Two-Means Test).

• Two statistics questions

  When would a researcher use a hypothesis test for the difference in two population proportions? Explain.

• Hypothesis Testing & Confidence Interval

  (STATISTICAL INFERENCES ABOUT TWO POPULATIONS) Use the following sample information to construct a 90% confidence interval for the difference in the two population means.