AP Stats

Which of the following is the best estimate of the 90th percentile for the weight of these bags of seed?

A. 40.3 pounds

The unusual point in the upper left part of the plot is for navy beans, with 15.8 grams of protein and 15.8 grams of carbs. Which of the following best describes how correlation would change if we removed navy beans from the data set?

A. The correlation would be closer to 1, because the remaining data would have a stronger positive relationship.

One hundred people work at Lagtime Internet Services...Assuming the president makes more than anyone else, which of the following statements about changes in measures of center and spread is true?

A. The mean and standard deviation will increase, but the median and IQR will stay the same.

...The Venn diagram below summarizes the distribution of these two categorical variables. Which of the two-way tables below conveys the same information?

B. **Study on paper

All of the following small data sets have a mean of 5. Which one has the lowest standard deviation?

B. 1 3 5 5 5 7 9

You randomly select one truck owner. What is the probability that he owns a Chevy, given that he has four wheel drive?

B. 32/80

Which of the following is the best description of a simple random sample of size n from a pop of size N.

B. Any method of sampling in which every group of individuals of size n is equally likely to be selected.

What is the principle purpose of control in a randomized comparative experiment?

B. Isolating the effect of the treatment variable by keeping all other variables the same in the treatment groups.

An airline has 10 daily flights from Philadelphia to Denver. To assess customer satisfaction, random sample of 15 passengers from each flight on a single day are asked to fill out a survey about their experience on the flight. What type of sample is this?

B. Stratified random sample

A bio teacher has just finished grading a quiz...He realizes he made a mistake and the highest grade should be 10 points higher. Which of the following sets of measurements will he have to recalculate?

B. The mean and standard deviation.

At right are box plots describing the distribution of prices paid for homes in two suburbs of Columbus, Ohio over a single 30-day period in 2012. Which of the following statements is supported by the information in this graph?

B. The median house price in Dublin is higher than the 75th percentile of house price in Westerville.

The customer service department...Which of the following are the mean and standard deviation of Y?

C. ***Study on paper

0..15 prob that he misses the bus.....If he is at the bus stop 3 consecutive days at 7:30, what is the approximate probability that he catches the bus all three days?

C. 0.614

Which of the following is not true about standard deviation?

C. If the units for the data are in inches, standard deviation is in square inches.

Which of the following statements about standard deviation is true?

C. Standard deviation is always a non-negative number.

The weights of adult male Labrador Retrievers are approximately normally distributed with a mean of 87 pounds and a standard deviation of 8 pounds. Which of the following statements is true?

C. The proportion of adult male Labrador Retrievers that weigh less than 80 pounds is approx equal to the proportion that weigh more 94 pounds.

At right is a stemplot of the weights of 18 adult Maine Coon Cats. Which of the following statements must be true about this distribution?

C. The standard score for a 14-pound cat is negative.

A recent investigation...the mean price in Montgomery was 13,200 with a standard deviation of 1000, In New York, the mean price was 12,800 with a standard deviation of 1800. Which of the following statements is true?

C. The standard score for a car priced at 15,000 would be higher in Montgomery than in New York.

You randomly select one truck owner. Which one of the following is true about the events "Owner has a Chevy" and "Owner's truck has four-wheel drive"?

C. These two events are not mutually exclusive, but they are independent.

For the track coach's study described in the previous exercise, which of the following best describes a conclusion that can be drawn?

C. We can determine whether the new training program improves race times more than the standard program for the distance runners in this study.

The cumulative relative frequency graph at right shows the distribution of lifespans for 39 U.S. presidents. Which of the following is closest to the 70th percentile of this distribution?

D. 77 years

You randomly select one truck owner. What is the probability that he owns a Dodge or has four wheel drive?

D. 90/125

The same 1200 tomatoes from above have a mean weight of 143 grams and a standard deviation of 35 grams. If the weights are normally distributed, approximately how many tomatoes weight between 73 grams and 178 grams?

D. 978

If you flip three coins, the probability of getting three heads is 0.125. Which of the following statements follows from this?

D. If you flip three coins 5000 times, the percent of time you get three heads will be very close 12.5%

The bar graph at right shows the distribution of religious affiliation around the world. Which of the following statement best describes what is wrong with this graph?

D. Starting the vertical scale at 5 distorts the relative frequency of the religions.

.......Some experts warn that we should not conclude that red cars are less safe than black cars, because of possible confounding. Which of the following best describes what this means?

D. Studies of this type are all observational, and it is not possible to separate the effect of car color from the type of people who choose to drive red cars.

The time it takes people to finish a certain kind of puzzle is strongly skewed right. Which of the following statements is true about the mean and median of this distribution?

D. The mean will be greater than the the median.

.......At the end of the questionnaire is an optional invitation to donate money to the organization. Which of the following statements about this survey is true?

D. The survey results will overestimate support for this political action committee in the entire population because people who respond are less likely to support an organization that asks for money.

Which of the following is closest to the 61st percentile of a standard normal distribution?

D. z=0.28

A special 20 sided die is constructed so that each face has either a 1,2,3, or 4 on it. The table below gives the probability of each value. Which of the following is the probability of rolling an odd number?

E. 0.6

The 5 number summary for the weights of 1200 tomatoes grown in a certain greenhouse was 90 113.5 140 161 236. How many tomatoes weighed less than 161 grams?

E. 900

A track coach.....He then compares race times within each group of two runners. What is the name for this kind of experimental design?

E. Matched pairs design.