AP stats in class

A researcher collected data on the cholesterol level, C, and the age, A, of 24 people selected at random. Using the data, the researcher calculated the least-squares regression line to be C = 182+2.2A and the standard error of the slope to be 0.38. If the conditions for inference are met, which of the following is closest to the value of the test statistic to test the hypotheses Ho: B = 0 versus Ha: B =/= 0?

• t = 5.79

• t = 0.38

• t = 0.17

• t = 2.2

A store manager selects a random sample of 30 receipts to estimate the mean purchase total. The mean is $93.80 the median is $75.80. However, a $500 gift card purchase is discovered, which the manager chooses to exclude. How will the removal affect the mean and median?

• The mean will decrease more than the median.

• The mean will decrease less than the median.

• The mean will increase more than the median

• The mean will stay the same, but the median will decrease.

• The mean will increase, but not as much as the median.

A realtor analyzes 50 homes listed for sale. The longer a home stays unsold, the more its price drops from the initial listing. The relationship between days on the market (x) and asking price (y) is modeled as y = 245,000 – 200x, with 75.4% of price variation explained. What is the correlation (r) between days on the market and asking price?

• 0.146

• -0.868

• 0.868

• -200

• 0.146

Tags

CCSS.HSS.ID.C.8

A study tests the accuracy of car gas gauges by assigning drivers specific gauge readings until empty to monitor. They measure the distance traveled when the gauge indicates that reading. After running out of gas, they report the distance traveled and the gauge reading. The regression analysis output is shown in the image.

What's the interpretation of the slope of the regression line for predicting actual distance based on gauge reading?

• Slope = 1.1889. The predicted distance the drivers were able to drive increases by 1.1889 miles for each additional mile reported by the gauge.

• Slope = 0.0457. The predicted distance the drivers were able to drive increases by 0.0457 miles for each additional mile reported by the gauge.

• Slope = –0.7928. The predicted distance the drivers were able to drive decreases by 0.7928 miles for each additional mile reported by the gauge.

• Slope = 1.1889. For each additional mile reported by the gauge, the drivers were able to drive an additional 1.1889 miles.

• Slope = 0.0457. For each additional mile reported by the gauge, the drivers were able to drive an additional 0.0457 miles.

Tags

CCSS.8.SP.A.3

At Central High School, the distribution of students across classes is 28% Freshmen, 26% Sophomores, 24% Juniors, and 22% Seniors. The student newspaper manager plans to survey 100 students, randomly selecting 28 Freshmen, 26 Sophomores, 24 Juniors, and 22 Seniors. What can be said about this sampling method?

• This is a simple random sample because students of every class have an equal chance of being selected

• This is a cluster random sample because there are 4 groups of students that are to be selected.

• This is a convenience sample because only 100 students are surveyed, which is a manageable size.

• This is a stratified random sample because a separate random sample is selected from each class.

• This is a systematic random sample because each class makes up approximately one-fourth of the student body.

Tags

CCSS.HSS.IC.B.3

A study compares customer satisfaction between computer companies offering tech support and those not offering it. A sample of 50 customers who purchased computers with tech support and 40 customers without it is analyzed. The study concludes that mean satisfaction rating is significantly higher among customers with tech support. What's the best description of this study?

• An experiment using a completely randomized design.

• An experiment using a randomized block design.

• An experiment using a matched pairs design.

• An observational study using a simple random sample.

• An observational study using a stratified sample.

Tags

CCSS.HSS.IC.B.3

To compare calorie burn rates, 40 volunteers are randomly assigned to either a crossfit class or a standard one. Participants wear calorie-tracking devices, and their average calorie burn is calculated for each class. Crossfit participants burned significantly more calories than those in the standard class. What's the most suitable conclusion?

• Crossfit caused higher calorie burn, and the conclusion can be generalized to all adults

  that work out.

• Crossfit caused higher calorie burn, and the conclusion can be generalized to all students of this instructor.

• Crossfit caused higher calorie burn, and the conclusion can not be generalized beyond those in the study

• No cause-and-effect, but an association between class type and calorie burn in all adult exercisers.

• No cause-and-effect, but an association between class type and calorie burn in all students of this instructor.

Tags

CCSS.HSS.IC.B.3

A school administrator estimates the proportion of students who text while driving by surveying students with parking permits. Each student is asked if they text while driving. The survey suggests only 2% of students with parking passes do so. What potential bias exists in this survey design, and what's its likely direction?

• The sample proportion is likely an underestimate of the population proportion due to response bias.

• The sample proportion is likely an underestimate of the population proportion due to undercoverage.

• The sample proportion is likely an underestimate of the population proportion due to nonresponse.

• The sample proportion is likely an overestimate of the population proportion due to response bias.

• The sample proportion is likely an overestimate of the population proportion due to undercoverage.

Tags

CCSS.HSS.IC.B.3

A guidance counselor reports that among Junior Pre-Calculus students, 48.5% signed up for AP Statistics, 52.5% for AP Calculus, and 10% for both. What's the probability a randomly selected student didn't sign up for either course next year?

• 0.09

• 0.11

• 0.19

• 0.91

• Not enough information is given to determine the probability.

Tags

CCSS.HSS.CP.B.7

A clothing company tests if offering first-time customers a coupon upon purchase will prompt them to make a second purchase. They randomly select 100 customers, with 60 receiving a $5 coupon for their next purchase. The rest don't receive any coupon. The table displays the number of customers in each group who made a second purchase within 30 days. Is making a second purchase independent of receiving a coupon?

• Yes, exactly half of the customers made a second purchase and half did not.

• Yes, the largest count in the table comes from those who were sent a coupon and made a second purchase within 30 days.

• No, the probability of making a second purchase is not equal to the probability of making a second purchase given that a coupon was sent.

• No, the probability of making a second purchase is the same whether or not a coupon was sent.

• It is impossible to draw a conclusion about independence because a coupon was not sent to exactly half of the customers.

Tags

CCSS.HSS.CP.A.3