Inference for Quantitative Data: Means unit test

A test on this unit alone, marked as a percentage and a letter grade — for the test your class is actually sitting, rather than for May. Answer everything, then submit once: seeing the answer to question 3 before attempting question 4 makes the final percentage meaningless.

Paper 1 Paper 2 Paper 3

Each paper is built from this unit’s 36 terms and is the same for everyone, so a teacher can assign “Unit 4, Paper 2” and every student sits the identical test. Multiple choice is marked objectively; the written sections you mark yourself against the model answer and rubric.

Suggested time 33 min 30 points0/17 attempted

Checking Normality from the sample graph

One-sample t statistic

Interpreting the magnitude of t

Reporting degrees of freedom

Choosing a significance level

Interpreting a t-interval for a difference

A two-mean interval containing zero

Why t rather than z

Two-sample t-interval

One-sample t-test statistic

t approaches z

Reading a t-table

Short answer 1. Define or explain: One-sample t-interval

3 pts

Short answer 2. Define or explain: Degrees of freedom, two samples

3 pts

Short answer 3. Define or explain: Conditions for t procedures

3 pts

Short answer 4. Define or explain: Robustness of t procedures

3 pts

Free response

6 pts

A researcher tests whether a new fertilizer increases mean tomato yield. She randomly assigns 40 plants to two groups of 20. New: x̄₁ = 5.4 kg, s₁ = 1.2. Standard: x̄₂ = 4.7 kg, s₂ = 1.1.

State the hypotheses.

Name the test and check conditions.

The test gives t = 1.92, df ≈ 37, p = 0.031. State a conclusion at α = 0.05 in context.

Explain what a Type I error would be here.