Stats Multiple Choice

You read in a book about a bridge that the probability that each of the four players is dealt exactly one ace is approx 0.11. This means that

C. In a very large number of bridge deals, the percent of deals on which each player have 1 ace will be very close to 11%.

The histogram below shoes the length of 140 songs recorded by the band Wilco. Which one of the following descriptions best fits this distribution?

C. Skewed right, centered at about 4.5, with several high outliers

Which of the following statements is false?

C. Switching the explanatory and response variables will change the correlation

two studies are run to compare the experiences of low income families receiving food stamps to those receiving cash subsidies. The first study interviews 50 families who have been in each government program for at least two years, well the second randomly assigns 50 families to each program and interviews them after two years. Which of the following is a true statement?

C. The first is an observational study, the second is an experiment

Which of the following is not a characteristic of the least-squares regression line?

C. The least-squares regression line minimizes the sum of squared residuals

If a distribution is skewed to the right, which of the folloiwng is true?

C. The mean must be greater than the median

Which of the following terms can be described as "the probability that one of it happens given that another of it is known to have happened"?

C. conditional probability

Which of the following statements is not true?

C. If two events are independent, then they just be mutually exclusive

An athlete suspected of using steroids is given two tests to operate independently of each other. Test A has a probability of 0.9 being positive the steroids have been used. Test B has a probability of 0.8 of being positive if steroids have been used. What is the probability that neither test is positive if the athlete has used steroids?

C. 0.02

The proportion of observations from a standard normal distribution that takes values larger than 0.75 is about

A. 0.2266

When rolling a fair die, you roll a 6 four times in a row. Given that each roll is independent, what is the probability that the next roll yields a 6 also?

A. 1/6

If Bird A were to dive 200 meters, what is the predicted value for the duration of the dive?

A. 5.45

Control groups are used in experiments in order to

A. Control the effects of outside variables on the outcome

A survey typically records many variables of interest to the researchers involved. Below are some of the variables from a survey conducted by the U.S. Postal Service. Which of the variables is categorical?

A. County of residence

If you want to see how well the price of oil predicts the price of gas, then you should make a scatterplot with _____ as the explanatory variable.

A. The price of oil

I said he was done to compare the lung capacity of coal miners to the lung capacity of farmworkers. The researchers study 200 workers of each type. Other factors that might affect lung capacity are smoking habits and exercise habits. The smoking habits of the two worker types are similar, but the coal miners generally exercise less than the farmworkers.

A. exercise

few people want to eat discolored french fries. Identify the experimental units, the treatment, and the response respectively in this question

A. potatoes, storage method, color and flavor

If P(A)=0.24, P(B)=0.52, and A and B are independent events, what is P(A or B)?

C. 0.6352

if you choose a card at random from a well shuffled deck of 52 cards, what is the probability that the card chosen is not a heart?

C. 0.75

If a player rolls a 2, 3, or 12 it is called craps what is the probability of getting craps or an even sum?

C. 20/36

Which of the following is not true about correlation?

C. Correlation can be used to describe a nonlinear relationship

Gina took the SAT in 1994 and scored 500. Her cousin Colleen took the SAT in 2013 and scored 530. Who did better on the exam, and how can you tell?

C. Gina-her standardized score is higher than Colleen's

Using the same study from #5, Bird A dove 300 meters for 7.13 minutes. What is the value of Bird A's residual?

B. 0.3

About what percent of cockroaches have weights between 76 and 84 grams?

B. 95%

A long jumper realized he measured his jumps wrong. He had to change the measurements. Which of the following will be affected by the correction of his jumps? choose two

B. Mean and D. Median

A researcher wishes to test a new drug developed to treat hypertension. A group of 40 hypertensive men and 60 hypertensive women is to be used. The experimenter randomly assigns 20 of the men and 30 of the women to the placebo and assigns the rest to the treatment. The major reason for a separate assignment for men and women is that

B. The new drug may affect men and women differently

Which of the following is an example of a single blind experiment? choose two

B. an experiment in which the test subjects are aware of who is receiving a placebo and who is receiving a therapy, but the researchers are unaware AND C. an experiment in which the researchers are aware of who is receiving a placebo and who is receiving a therapy, but the test subjects are unaware

The community intervention trial for smoking cessation asked whether a community wide advertising campaign would reduce smoking. The researchers located 11 pairs of communities, each pair is similar in location, size, economic status, and so on. One community in each pair participated in the advertising campaign and the other did not. This is an example of

C. matched pairs design

A sales representative wishes to survey her client base of 47 companies. She has 47 business cards, all identical in size, from her contacts in the companies, and decides to drop them all in a small box, shake them up, and reach in to pick five cards for her sample. this is an example of

C. simple random samplinh

Using the output from the least-squares regression analysis shown above, determine the equation of the least-squares regression line.

C. y^=87.974-0.060934x

The most common bet in craps is the passline. A passline bettor wins immediately if either seven or an 11 comes up on the first role. This is called a natural. What is the probability that a natural does not occur?

E. 28/36

Given P(A)=0.4, P(B)=0.3, P(B|A)=0.2. What is P(AnB) and P(AuB)

E. P(AnB)=0.08, P(AuB)=0.62

Pete receives his score report: he got a 63, which placed him at the 73rd percentile. This means that

E. Pete did better than about 73% of the test takers

Using the output form the regression analysis, determine the correlation.

D. 0.407

Scored on the ACT follow a bell-shaped distribution with mean 21 and SD 5. Wayne's standardized score on the ACT was -0.6. What was Wayne's actual ACT score?

D. 18

Which of the following are resistant to outliers?

D. The median and the IQR

Can texting make you healthier? Researchers randomly assigned 700 Australian adults to either receive usual healthcare or usual healthcare plus automated text messages with positive messages. The group that received the text messages showed a statistically significant increase in physical activity. What is the meaning of statistically significant in this context?

E. The difference in physical activity for the two groups is larger than the difference that could be expected to happen by chance alone

researchers randomly selected 1700 people from Canada who had never suffered a heart attack and rated the happiness of each person. 10 years later, the researchers followed up with each person and found that people who are initially rated as happy or less likely to have a heart problem. Which of the following is the most appropriate conclusion based on the study?

E. happier people in the study were less likely to have heart problems