AP Statistics Review #1-10

Experimental Design (1)
Which of the following is a true statement?

• A) While properly designed experiments can strongly suggest cause-and-effect relationships, a complete census is the only way of establishing such a relationship.
• B) If properly designed, observational studies can establish cause-and-effect relationships just as strongly as  properly designed experiments.
• C) Controlled experiments are often undertaken later to establish cause-and-effect relationships first suggessted by observational studies.
• D) A useful approach to overcome bias in observational studies is to increase the sample size.

Tags

CCSS.HSS.IC.B.3

Experimental Design (3)
In an experiment, the control group should receive

• A) Treatment opposite the experimental group.
• B) The same treatment as the experimental group without knowing they are receiving the treatment.
• C) A procedure identical to the experimental group except for recieving the treatment under examination.
• D) A procedure identical to the experimental group except for a random decision on receiving the treatment under examination.

Tags

CCSS.HSS.IC.B.3

Normal Curve (2)
Two Classes take the same exam. Suppose a certain score is at the 40th percentile for the first class and at the 80th percentile for the second class.  Which of the following is the most reasonable conclusion?

• A) Students in the first class generally scored higher than students in the second class.
• B) Students in the second class generally scored higher than students in the second class.
• C) A score at the 20th percentile for the first class is at the 40th percentile for the second class.
• D) One of the classes has twice the number of students as the other.

Tags

CCSS.7.SP.B.4

Inference w/ Intervals (4)
In a random sample of Toyota car owners, 83 out of 112 said they were satisfied with the Toyota front-wheel drive, while in a similar survey of Subaru owners, 76 out of 81 said they were satisfied with the Subaru four-wheel drive.  A 90% confidence interval estimate for the difference in proportions between Toyota & Subaru car owners who are satisfied with their drive systems is reported to be -0.197 ± 0.081.  Which is a proper conclusion?

• A) The interval is invalid because probabilities cannot be negative.
• B) We are 90% confident that the difference in proportions between Toyota and Subaru car owners who are satisfied with their drive systems is between -0.278 and -0.116.
• C) The interval is invalid because it does not contain zero.
• D) Subaru owners are approximately 19.7% more satisfied with their drive systems than are Toyota owners.

Tags

CCSS.HSS.IC.B.4

Experimental Design (5)
In a study of the effect of music on worker productivity, employees were told that a different genre of background music would be played each day and the corresponding production outputs noted.  Every change in music resulted in an increase in production.  This is an example of

• A) the effect of a treatment unit.
• B) The placebo effect.
• C) sampling error.
• D) voluntary response bias

Tags

CCSS.HSS.IC.B.3

Inference Chi-Square (6)

• A) (325)(450)/700
• B) (450)(700)/1000
• C) (325)(450)/1000
• D) (325)(700)/100

LSRL (7)
Which of the following statements about the correlation coefficient is true?

• A) The correlation coefficient and the slope of the regression line may have opposite signs.
• B) A correlation of 1 indicates a perfect cause-and-effect relationship between the variables.
• C) Correlations of +0.87 and -0.87 indicate the same degree of clustering around the regression line.
• D) A correlation of 0 shows little or no association between two variables.

Tags

CCSS.HSS.ID.B.6B

Random Variables (8)
Suppose X and Y are random variables with E(X) = 780, var(X) = 75, E(Y) = 430, and var(Y) = 25.  Given that X and Y are independent, what is the variance of the random variable X - Y?

• A) 75 - 25
• B) 75 + 25
• C) √(75 - 25)
• D) √(75 + 25)

Sample Methods (9)
What is a sample?

• A) A measurable characteristic of a population.
• B) A set of individuals having a characteristic in common
• C) A value calculated from raw data.
• D) A subset of a population

Tags

CCSS.7.SP.A.1

CCSS.HSS.IC.A.1

A histogram of the cholesterol levels of all employees at a large law firm is shown. (See answer choices in image)

• A

• B

• C

• D