AP Statistics Unit 6

Margin of error equals:

• Critical Value ∗ standard Error

• z*

• 1.96

• Standard Error

What do we use to estimate unknown parameters?

• Hypothesis Test

• Confidence Interval

• Trig Identity

• Guess and check

When conducting a significance test for the difference in proportions, why do we pool the data when finding standard error?

• Because we like to swim

• Because we assume p1 = p2 in Ho

• Because the sample sizes are always equal

• To be safe and make sure we don't underestimate the standard error

• Because we don't the standard deviation.

If a researcher were to interview every 10th student who enters the school in the morning. What type of sampling is this?

• simple random

• voluntary response

• systematic

• convenience

If a researcher were to assign each car in a dealership a number and then use a random-number table to select the cars to be inspected, what type of sampling is this?

• systematic

• simple random sample

• convenience

• Self - selected (volunteer)

Disneyland often surveys its guests as they exit a restaurant during their visit. The surveyor stands at the restaurant exit, counts the number of people leaving, and surveys every 25th guest.
This is a form of:

• Simple Random Sample

• Stratified Random Sample

• Voluntary Response

• Systematic Random Sampling

Biased or Random?

Chloe and Danna want to determine the favorite subject of all students in the middle school. So they place every middle school student's name in a bucket and choose 30 to poll.

• Biased sample

• Random sample

You want to take a simple random sample (SRS) of 50 of the 816 students who live in a dormitory on campus. You label the students 001 to 816 in alphabetical order. In the table of random digits, you read the entries (shown in the image).

The first three students in your sample have labels

• 955, 929, 400

• 400, 769, 769

• 559, 294, 007

• 929, 400, 769

• 400, 769, 335

The transportation department of a large city wants to estimate the proportion of residents who would use a system of aerial gondolas to commute to work. The gondolas would be part of the city’s effort to relieve traffic congestion. The department asked a random sample of residents whether they would use the gondolas. The residents could respond with yes, no, or maybe. Which of the following is the best description of the method for data collection used by the department?

• A census

• A sample survey

• An experiment with a completely randomized design

• An experiment with a randomized block design

• An experiment with a matched-pairs design

A compact disc (CD) manufacturer wanted to determine which of two different cover designs for a newly released CD will generate more sales. The manufacturer chose 70 stores to sell the CD. Thirty-five of these stores were randomly assigned to sell CDs with one of the cover designs and the other 35 were assigned to sell the CDs with the other cover design. The manufacturer recorded the number of CDs sold at each of the stores and found a significant difference between the mean number of CDs sold for the two cover designs. Which of the following gives the conclusion that should be made based on the results and provides the best explanation for the conclusion?

• It is NOT reasonable to conclude that the difference in sales was caused by the different cover designs because this was not an experiment.

• It is NOT reasonable to conclude that the difference in sales was caused by the different cover designs because there was no control group for comparison.

• It is NOT reasonable to conclude that the difference in sales was caused by the different cover designs because the 70 stores were not randomly chosen.

• It is reasonable to conclude that the difference in sales was caused by the different cover designs because the cover designs were randomly assigned to stores.

• It is reasonable to conclude that the difference in sales was caused by the different cover designs because the sample size was large.