2026/2027
Gmail:
27
ALC Exam STA4211
Questions with Detailed
Verified Answers
Parameter vs statistic Ans: A parameter is a measure that describes the entire
population, whereas a statistic describes a sample of the population.
sampling distribution Ans: probability distribution of a given statistic based on
a random sample
unbiased estimator Ans: An unbiased estimator is an accurate statistic that's
used to approximate a population parameter. "Accurate" in this sense means
that it's neither an overestimate nor an underestimate. If an overestimate or
underestimate does happen, the mean of the difference is called a "bias."
bias( thetahat) = E(thetahat) - (thetahat)
margin of error Ans: In a confidence interval, the range of values above and
below the sample statistic is called the margin of error.
standard error Ans: The standard error is an estimate of the standard
deviation of a statistic. The standard error is computed from known sample
statistics.
interpreting a confidence interval Ans: "We are 95% confident that the mean
time it takes all workers in this city to get to work is between 18.3 and 23.7
minutes."
increase in sample size or decrease in confidence level Ans: more precise or
narrow confidence interval
type 1 and type 2 error Ans: Type 1- rejecting the null when it is actually true
Type 2- fail to reject null when it is actually false (dangerous)
Gmail:
27
ALC Exam STA4211
Questions with Detailed
Verified Answers
Parameter vs statistic Ans: A parameter is a measure that describes the entire
population, whereas a statistic describes a sample of the population.
sampling distribution Ans: probability distribution of a given statistic based on
a random sample
unbiased estimator Ans: An unbiased estimator is an accurate statistic that's
used to approximate a population parameter. "Accurate" in this sense means
that it's neither an overestimate nor an underestimate. If an overestimate or
underestimate does happen, the mean of the difference is called a "bias."
bias( thetahat) = E(thetahat) - (thetahat)
margin of error Ans: In a confidence interval, the range of values above and
below the sample statistic is called the margin of error.
standard error Ans: The standard error is an estimate of the standard
deviation of a statistic. The standard error is computed from known sample
statistics.
interpreting a confidence interval Ans: "We are 95% confident that the mean
time it takes all workers in this city to get to work is between 18.3 and 23.7
minutes."
increase in sample size or decrease in confidence level Ans: more precise or
narrow confidence interval
type 1 and type 2 error Ans: Type 1- rejecting the null when it is actually true
Type 2- fail to reject null when it is actually false (dangerous)
