bias
prejudice in favor of or against one thing, person, or group compared with another, usually in a way considered to be unfair.
A coin is tossed three times. What is the probability that it lands on heads exactly one time?
0.375
Which of the following statements are true?I. Categorical variables are the same as qualitative variables. II. Categorical variables are the same as quantitative variables. III. Quantitative variables can be continuous variables.
I and III
Which of the following statements is true. I. The standard error is computed solely from sample attributes. II. The standard deviation of a population is computed solely from sample attributes. III. The standard error is a measure of central tendency.
I only
Which of the following statements are true?
I. Random sampling is a good way to reduce response bias.
II. To guard against bias from undercoverage, use a convenience sample. III. Increasing the sample size tends to reduce survey bias
IV. To guard against nonresponse bias, use a mail-in survey.
None of the above
Suppose a simple random sample of 150 students is drawn from a population of 3000 college students. Among sampled students, the average IQ score is 115 with a standard deviation of 10. What is the 99% confidence interval for the students' IQ score?
115 + 2.1
An urn contains 6 red marbles and 4 black marbles. Two marbles are drawn with replacement from the urn. What is the probability that both of the marbles are black?
0.16
Which of the following is a discrete random variable?
I. The average height of a randomly selected group of boys.
II. The annual number of sweepstakes winners from New York City.
III. The number of presidential elections in the 20th century.
II only
what is the definition of undercoverage bias
Undercoverage occurs when some members of the population are inadequately represented in the sample.
Suppose we want to estimate the average weight of an adult male in Dekalb County, Georgia. We draw a random sample of 1,000 men from a population of 1,000,000 men and weigh them. We find that the average man in our sample weighs 180 pounds, and the standard deviation of the sample is 30 pounds. What is the 95% confidence interval.
180 +/- 1.86
Bob is a high school basketball player. He is a 70% free throw shooter. That means his probability of making a free throw is 0.70. What is the probability that Bob makes his first free throw on his fifth shot?
0.0057
Which of the following statements are true?
I. A sample survey is an example of an experimental study. II. An observational study requires fewer resources than an experiment. III. The best method for investigating causal relationships is an observational study.
None of the above
Undercoverage,Nonresponse bias,Voluntary response bias
A card is drawn randomly from a deck of ordinary playing cards. You win $10 if the card is a spade or an ace. What is the probability that you will win the game?
4/13
Suppose a researcher conducts an experiment to test a hypothesis. If she doubles her sample size, which of the following will increase? I. The power of the hypothesis test. II. The effect size of the hypothesis test. III. The probability of making a Type II error.
I only
A major metropolitan newspaper selected a simple random sample of 1,600 readers from their list of 100,000 subscribers. They asked whether the paper should increase its coverage of local news. Forty percent of the sample wanted more local news. What is the 99% confidence interval for the proportion of readers who would like more coverage of local news?
0.37 to 0.43
P(A ∪ B) = P(A) + P(B) - P(A ∩ B)
and
P(A ∪ B) = P(A) + P(B) - P(A)P( B | A )
With respect to experimental design, which of the following statements are true?
I. Blinding controls for the effects of confounding.
II. Randomization controls for effects of lurking variables.
III. Each experimental factor has one treatment level.
II only