Sample Means vs Sample Proportions

• A) Randomization Condition
• B) 10% Condition
• C) Independent Samples Condition
• D) Nearly Normal Distribution Condition

A manufacturer receives parts from two suppliers. An SRS of 400 parts from Supplier 1 contains 20 defective parts, while an independent SRS of 100 parts from Supplier 2 contains 10 defective parts. Let p₁ and p₂ be the proportions of defective parts made by Supplier 1 and Supplier 2, respectively. Is there evidence of a significant difference in the proportions of defective parts made by these two suppliers?
To answer this question, you test the hypotheses 
H₀ : p₁ - p₂ = 0 against H_A : p₁ - p₂  ≠ 0 . Which of the following is closest to the P-value of the test?

• 0.9398

• 0.0602

• 0.0301

• It cannot be determined.

Jimmy is interested in comparing the fitness level of the members of his gym to the levels at a competing gym. He randomly selected 125 members of his gym and found 75 passed a fitness test. 70 of 95 at the other gym passed. Which interval estimates, with 96% confidence, the difference in proportion of members in Jimmy's gym who can pass the test and the proportion from the other gym who can pass?

• (-0.2404, -0.033)

• (-0.2602, -0.0135)

• (-0.2661, -0.0076)

• (-0.3490, -0.1099)

• (-0.3547, -0.1042)

Select the correct description

• Average Percent

• Population Proportion

• Sample Proportion

• Percent Slope of a Distribution

What does this symbol represent?

• population proportion

• parameter

• sample proportion

• population sample

Would it be unusual to get a sample proportion of .35 or higher? Explain

• Yes because only 10 of the sample proportions 0.35.

• No because 23/100 of the sample proportions were 35% or higher. 23% is not unusual

• Yes because we should get 25% every time.

Define the symbol.

• sample size

• standard deviation of sampling distribution of sample means

• population proportion

• sample proportion

The Gallup Poll asked a random sample of 1785 adults whether they attended church during the past week.  Let p-hat be the proportion of people in the sample who attended church.  A newspaper report claims that 40% of all U.S. adults went to church last week.  Suppose this claim is true. 
What is the mean of the sampling distribution of p-hat?

• 0.4

• 0.44

• 0.56

• 0.6

28% of all Suncoast students believe in Santa. You take a sample of 50 students and find that 15 of them believe in Santa. What does 15/50 represent?

• n

• P

• phat

• standard deviation

When sampling from a population with proportion p, the distribution of sample proportions (p-hat) will vary. What will be the mean of all possible sample proportions?

• p