Stats

the number of sweatshirts a vendor sells daily has the following probability distribution. if each sweatshirt sells for $25, what is the expected daily total dollar amount taken in by the vendor from the sale of sweatshirts?

$38.00

random variable X is normally distributed with mean 10 and std dev 3... which of the following describes distribution of Y-X?

-1 5

a lsr line was fitted to the weights versus age of a group of many young children. which of the following is the residual weight for this child?

-4.6

a game of chance is played in which x, the number of points scored in each game, has the distribution shown above. which of the following is true for the sampling distribution of the sum, y, of the scores when the game is played twice?

0-4 with respective probabilities

all bags entering a research facility are screened. what is the probability that a bag that triggers the alarm will actually contain forbidden material?

0.00640

the distribution of the diameters of a particular variety of oranges is approx normal with a std dev of 0.3 inches. how does the diameter of an orange at the 67th percentile compare with the mean diameter?

0.132 inches above mean

the probability of obtaining a head when a certain coin is flipped is about 0.65....

0.37

which of the following differences in cumulative relative frequencies gives the proportion of trees that are 12 inches to 16 inches, inclusive, in diameter?

0.726-0.325

the correlation between two scores x and y is 0.8. if both the x scores and the y scores are converted to z-scores, then the correlation between the z-scores for y would be...

0.8

a fair coin is to be flipped 5x. the first 4 flips land heads up. probability of heads on 5th flip?

1/2

ten percent of all dynamite mints candies are orange and 45 percent of all holiday mints candies are orange

13.75 and 2.905

90% of people who have a particular disease will have a positive result on a given diagnostic test

14%

the number of points, x, scored in a game has the probability distribution below

2

exercise physiologists are investigating the relationship between lean body mass and resting metabolic rate in sedentary males. which of the following is the best interpretation of the value of the slope of the regression line?

22.563 calorie increase per kg

according to this definition, what is the diameter, in inches, of the smallest tree that is an outlier?

34

the weights of a population of adult male gray whales are approx.... this whale has same z-score of hump back whale who weighs...

39,000 kg

in a carnival game, a person can win a prize by guessing which one of 5 identical boxes contains the prize. if a person makes 4 guesses, what is the probability that the person wins a prize exactly 2 times?

4 choose 2

suppose that the distribution of a set of scores has a mean of 47 and a std dev of 14. if 4 is added to each score, what will be the mean and std dev of the distribution of new scores?

51 14

Which of the following is closest to the percentile rank of a resident from this street who traveled 85 miles to work that week?

70

some descriptive statistics for a set of test scores are shown above. what score did this student receive on the test?

779.42

a random sample of 25 households from the mountain view school district was surveyed.

8 years old to less than 10 years old

consider n pairs of numbers. of the following, which could be the lsr line?

8.5+0.3x

the histogram below displays the times, in minutes, needed for each chimp in a sample of 26 to complete a simple navigational task. it was determined that the largest observation... which of the following box plots reps histogram?

D

consider a data set of positive values, at least two of which are not equal. which of the following sample statistics will be changed when each value in this data set is multiplied by a constant whose absolute value is greater than 1?

I, II, and III

an experiment has 3 mutually exclusive outcomes A, B, and C. which of the following must be true?

II and III only

a group of students has 60 houseflies in a large container... which of the following methods will be most likely to result in 3 comparable groups of 20 house flies each?

LONGEST ANSWER

let x represent random variable whose distribution is normal with mean of 100 and std dev 10. which of the following is equal to P(X>115)?

P(X<85)

each of 100 laboratory rats has available both plain water and a mixture of water and caffeine in their cages. which of the following conclusions is justified on the basis of this study?

about 18% of the variation can be explained

which is NOT a characteristic of stratified random sampling?

all subsets have equal chance o being selected

which of the following is a key distinction between well designed experiments and observational studies?

an experiment can show a direct cause and effect relationship, observational study cannot

Janelle collected data on the amount of time in minutes each person in a large sample of customers spent in a local store...

approximately half of the males

suppose that 30% of the subscribers to a cable television service watch the shopping channel at least once a week. which of the following assignments of the digits 0-9 would be appropriate for modeling an individual subscriber's behavior in this simulation?

assign "0,1,2" as watching the shopping channel at least once weekly

the statistics below provide a summary of the distribution of heights in inches for a random sample of 200 children. about 100 children in the sample have heights that are..

between 43 and 48 inches

a certain type of remote control car has a fully charged battery at the time of purchase

between 75 and 82.5

a dog food company wishes to test a new high protein formula

block on dog breed randomly assign to both

automobile brake pads are either metallic or nonmetallic. this experiment would best be done

by blocking on car size

the table above shows the sample size, mean, and median for two samples of measurements. what is the median for the combined 47 measurements?

cannot be determined

the buyer for an electronics store wants to estimate the proportion of defective wireless game controllers...

cluster random sample

the box plots shown above summarize two data sets, I and II. based on the box plots, which of the following statements CANNOT be justified?

data set I and data set II have the same number of data points

a volunteer for a mayoral candidate's campaign periodically conducts polls. the main purpose of this is to..

decrease std dev

the director of a technical school was curious about whether there is a relationship between students who complete one of the school's most popular health sciences

did not complete the program but completed more advanced studies

a researcher wishes to test a new drug developed to treat hypertension. the major reason for separate assignment of men and women is...

drug may affect men and women differently

a wildlife biologist is interested in the relationship between the number of chirps per minute and temperature. which of the following best describes the meaning of the slope of the lsr line?

estimated number of chirps by 3.41

in which of the following situations would it be most difficult to use a census?

fish in lake michigan

in a certain game, a fair die is rolled and a player gains 20 points if the die shows a 6. what would be the expected total gain or loss for the player?

gain of 83

the figure above shows a cumulative relative frequency histogram of 40 scores on a test given in ap stat. which of the following conclusions can be made from the graph?

greater variability

jason wants to determine how age and gender are related to political party preference in his town. of the following, which is the most important observation about jason's plan?

he will be unable to tell

in a recent survey, 60 randomly selected married couples from the same town were asked to rate their overall quality of living

husbands tended to rate higher

which of the following statements is true for two events, each with probability greater than 0?

if they are mutually exclusive, they cannot be independent

traffic data revealed that 35% of automobiles traveling along a portion of an interstate highway were exceeding the legal limit

it cannot be determined from the information given

publishers of a magazine wish to determine what proportion of the magazine's 50k subscribers are pleased with their subscription

mail surveys to 1,000 subscribers randomly selected from all subscribers

the stem plot below shows the yearly earnings per share of stock for two different companies over 16 yr period. which is true?

mean of earnings of A higher than mean of earnings of B

a botanist is studying the petal lengths measured in millimeters of two species of lilies. based on these box plots which of the following is a correct conclusion about the data collected in this study?

more petal lengths less than 30 mm for species B than A

100 people were interviewed and classified according to their attitude toward small cars and their personality type. which of the following is true?

more than half have type A and positive personality

a delivery service places packages in large containers before flying them cross country. the weights of the two containers..

negative correlation

a new medication has been developed to treat sleep-onset insomnia. of the following, which is the best method for obtaining this information?

new drug to one group and old drug to the other group

lynn is planning to fly from new york to la and will take the airtight airlines flight that leaves at 8 AM. of the following, which is the most reasonable explanation for how that probability could have been estimated?

on previous days scheduled it arrived 70% on time

A large SRS of people aged 19-30 living in the state of Colorado...

only people aged 19-30 living in the state of Colorado

a television news editor would like to know how local registered voters would respond to the question "are you in favor of the school bond measure that will be voted on in an upcoming special election?" which one of the following is the most obvious reason

people who feel strongly are likely to respond

a data set of test scores is being transformed by applying the following rule to each of the raw scores

range

a high school physics teacher was conduction an experiment with his class on the length of time it will take a marble to roll down a sloped chute. what effect will this have on the correlation of the two variables?

remain 0.964

a new restaurant is interested in determining the best time-temperature combination for roasting a five pound cut of lamb

replication

george and michelle each claimed to have the better choco chip cookie recipe. which of the following statements about this study is false?

same questionnaire

a small town employs 34 salaried, nonunion employees. which of the following is least likely to be useful to readers for this purpose?

scatter plot of B versus A

lauren is enrolled in a very large college calculus class. assuming the scores on each exam were approximately normally distributed, on which exam did lauren score better relative to the rest of the class?

she scored about equally on both exams

a high school statistics class wants to conduct a survey to determine what percentage of students in the school would be willing to pay a fee for participating in after school activities. this plan is an example of which type of sampling?

stratified random

a local real estate magazine used the median instead of the mean when it reported the sat score of the average student who attends Groveland High School

the mean is affected by skewness

a study of existing records of 27,000 automobile accidents involving children in michigan found that about 10% of children who were wearing a seatbelt were injured. which of the following statements should NOT be included in a summary report about this study?

this study clearly demonstrates that seat belts save children from injury

a distribution of test scores is not symmetric. which of the following is the best estimate of the z-score of the third quartile?

this z-score cannot be estimated form the info given

each person in a simple random sample of 2,000 received a survey and 317 responded. how could nonresponse cause the results of the survey to be biased?

those who did not respond may differ in some important way from those who did not respond