MGSC EXAM 3 CERTIFICATION TEST 2026
QUESTIONS AND VERIFIED ANSWERS ALREADY
PASSED
◉ The variability of the sample mean is measured by the:
Answer: Standard error
◉ When the center of the sampling distribution of a statistic is equal
to the parameter, the statistic is:
Answer: an unbiased estimator
◉ In statistics, the word expected means:
Answer: average
◉ Bootstrapping in statistics involves:
Answer: taking random samples with replacement from the original
data set
◉ Bootstrapping uses ___ to describe the sampling distribution
Answer: Theory
◉ In practice, which R squared do we care about?
,Answer: OOS
◉ In regularization, we penalize:
Answer: Complexity
◉ In regularization, we all lambda the:
Answer: penalty
◉ How many models does lass regression create?
Answer: 100
◉ Which IC does the gamlr function use by default?
Answer: AICc
◉ The sampling distribution is the
Answer: distribution of a statistic (like the mean) across many
repeated samples
◉ What does this line do?(xbar <- mean(ames$SalePrice))
Answer: Calculates the sample mean of SalePrice and stores it in
xbar. The parentheses also print the result
, ◉ What does ames$SalePrice mean?
Answer: It selects the SalePrice column from the data frame ames
◉ What does this line do?(se <-
sd(ames$SalePrice)/sqrt(nrow(ames)))
Answer: Computes the standard error of the sample mean using
sample SD divided by square root of sample size
◉ What does sd(ames$SalePrice) do?
Answer: Finds the sample standard deviation of home sale prices
◉ n(row) is essentially the:
Answer: sample size
◉ What does this line do?xbar + c(-1.96,1.96)*se
Answer: Builds a 95% confidence interval by taking the estimate
plus and minus 1.96 standard errors
◉ What does c(-1.96,1.96) do?
Answer: Creates a two-number vector so R returns both the lower
and upper confidence interval endpoints
QUESTIONS AND VERIFIED ANSWERS ALREADY
PASSED
◉ The variability of the sample mean is measured by the:
Answer: Standard error
◉ When the center of the sampling distribution of a statistic is equal
to the parameter, the statistic is:
Answer: an unbiased estimator
◉ In statistics, the word expected means:
Answer: average
◉ Bootstrapping in statistics involves:
Answer: taking random samples with replacement from the original
data set
◉ Bootstrapping uses ___ to describe the sampling distribution
Answer: Theory
◉ In practice, which R squared do we care about?
,Answer: OOS
◉ In regularization, we penalize:
Answer: Complexity
◉ In regularization, we all lambda the:
Answer: penalty
◉ How many models does lass regression create?
Answer: 100
◉ Which IC does the gamlr function use by default?
Answer: AICc
◉ The sampling distribution is the
Answer: distribution of a statistic (like the mean) across many
repeated samples
◉ What does this line do?(xbar <- mean(ames$SalePrice))
Answer: Calculates the sample mean of SalePrice and stores it in
xbar. The parentheses also print the result
, ◉ What does ames$SalePrice mean?
Answer: It selects the SalePrice column from the data frame ames
◉ What does this line do?(se <-
sd(ames$SalePrice)/sqrt(nrow(ames)))
Answer: Computes the standard error of the sample mean using
sample SD divided by square root of sample size
◉ What does sd(ames$SalePrice) do?
Answer: Finds the sample standard deviation of home sale prices
◉ n(row) is essentially the:
Answer: sample size
◉ What does this line do?xbar + c(-1.96,1.96)*se
Answer: Builds a 95% confidence interval by taking the estimate
plus and minus 1.96 standard errors
◉ What does c(-1.96,1.96) do?
Answer: Creates a two-number vector so R returns both the lower
and upper confidence interval endpoints
