AP STATS: Chapter 22 - 23 Test Review 2018

What additional condition must be checked for a 2-proportion test or interval compared to a 1-proportion test or interval?

• You must make sure that the samples are random
• You must make sure that the two samples are independent from one another
• You must make sure that the sum of the samples' sizes are smaller than 10% of the whole population
• The conditions are exactly the same

At a baseball game, 42 of 65 randomly selected people own an iPod. At a rock concert occurring at the same time across town, 34 of 52 randomly selected people own an iPod. A researcher wants to test the claim that the proportion of iPod owners at the two venues is different. A 90% confidence interval for the difference in population proportions(game − concert) is (−0.154, 0.138). Which of the following gives the correct outcome of the researcher’s test of the claim?

• Because the confidence interval includes 0, the researcher can conclude that the proportion of iPod owners at the two venues is the same.
• Because the center of the interval is –0.008, the researcher can conclude that a higher proportion of people at the rock concert own iPods than at the baseball game.
• Because the confidence interval includes 0, the researcher cannot conclude that the proportion of iPod owners at the two venues is different.
• Because the confidence interval includes more negative than positive values, the researcher can conclude that a higher proportion of people at the rock concert own iPods than at the baseball game.

For a simple random sample of 100 cars of a certain popular model in 2012, it was found that 20 had a certain minor defect in the brakes. For an independent SRS of 400 cars of the same model in 2009, it was found that 50 had the same defect. A 90% confidence interval for p₂₀₁₂– p₂₀₀₉ is (approximately)

• 0.075 ± 0.085
• 0.075 ± 0.071
• 0.075 ± 0.043

In a simple random sample of 100 households in 2000, 43 had some credit card debt. In another simple random sample of 150 households in 2012, 72 had some credit card debt. We want to construct a confidence interval for the difference in the proportion of households with credit card debt between 2012 and 2000. Which of the following is the correct standard error estimate for this interval?

• 
• 
• 

In a simple random sample of 100 households in 2000, 43 had some credit card debt. In another simple random sample of 150 households in 2012, 72 had some credit card debt. Which of the following is the correct test statistic for testing the hypothesis H₀ : p₂₀₀₀ - p₂₀₁₂ = 0, that there is no difference in the proportion of households with credit card debt in these two years?

• 
• 
• 

 In a simple random sample of 100 cars of a certain popular model in 2010, it was found that 20 had a certain minor defect in the brakes. For an independent SRS of 400 cars of the same model in 2011, it was found that 50 had the same defect. Let p₁ and p₂ be the proportions of all cars of this model in 2010 and 2011, respectively, that have the defect. We wish to test H₀ : p₁ - p₂ = 0 against H_A : p₁ - p₂ > 0 . Which of the following is closest to the P-value for this test?

• 0.0418
• 0.0536
• 0.0268

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

What is the t value associated with 90% confidence and a sample size of 15?

• 1.341
• 1.345
• 1.761
• 1.753

Tags

CCSS.HSS.IC.A.1

CCSS.HSS.IC.B.4

What is the degrees of freedom equal to?

• n
• n+1
• 1-n
• n-1

In a crash test of 15 troopers, collision repair costs are found to have a distribution that is approximately normal, with a mean of $1800 and a sample standard deviation of $950. Construct a 99% confidence interval for the repair cost. 

• (1069.77, 2530.23)
• (1077.13, 2522.87)
• (1167.15, 2432.85)
• None of these.

Tags

CCSS.HSS.IC.A.1

CCSS.HSS.IC.B.4

CCSS.HSS.ID.A.4