Tests comparing two population means

STA 121. Practice questions, not past papers.

Lessons

• Separate independent and paired designs
• Use an appropriate alternative

Practice questions

1. A pooled two-sample t procedure assumes what about population variances?

   Statistics study edition practice item Q268; Source: T113-116

2. Independent pooled t-test degrees of freedom equal what?

   Statistics study edition practice item Q269; Source: T113-116

3. Which data should instead be analysed through within-pair differences?

   Statistics study edition practice item Q270; Source: T113-116

4. The standard error for independent known-variance mean differences is what?

   Statistics study edition practice item Q271; Source: T113-116

5. Independent samples have means 54 and 50, n1=n2=25 and known SDs 5 and 5. Find z for a null difference of zero. Give the value to 4 decimal places.

   Statistics study edition practice item Q272; Source: T113-114

6. Independent pooled samples have n1=8 and n2=6. Find t-test degrees of freedom.

   Statistics study edition practice item Q273; Source: T114

7. A pooled t test assumes equal population _____.

   Statistics study edition practice item F089; Source: T113-116

8. For two independent pooled samples, df=n1+n2-_____.

   Statistics study edition practice item F090; Source: T113-116

Topic gap report