Econ 120b midterm Test Questions
and Answers 2025-2026 Updated.
confidence interval - Answer
covariance - Answer
correlation formula - Answer = Covariance/(std x * std y)
simple random sampling - Answer Y1 and Y2 are independently and identically distributed
law of large numbers - Answer Y bar becomes a consistent estimator of u (pop mean) when n
gets larger and larger
Central Limit Theorem - Answer The theory that, as sample size increases, the distribution of
sample means of size n, randomly selected, approaches a normal distribution.
E[ u (pop mean) = - Answer E[ u (pop mean) = pop mean
the larger the variance of x: what happens to variance of b1 - Answer variance to b1 gets
smaller
spread is what proportional to n - Answer spread is proportional to n
normal distribution - Answer N(mean, variance)
N(0,1) (CLT)
Why use Y bar to estimate uy - Answer Y bar is unbiased: E(Y bar) = uy
Y bar is consistent: Y bar --> uy
p
Y bar is the least squares estimator of uy (lecture slides 1 page 44)
and Answers 2025-2026 Updated.
confidence interval - Answer
covariance - Answer
correlation formula - Answer = Covariance/(std x * std y)
simple random sampling - Answer Y1 and Y2 are independently and identically distributed
law of large numbers - Answer Y bar becomes a consistent estimator of u (pop mean) when n
gets larger and larger
Central Limit Theorem - Answer The theory that, as sample size increases, the distribution of
sample means of size n, randomly selected, approaches a normal distribution.
E[ u (pop mean) = - Answer E[ u (pop mean) = pop mean
the larger the variance of x: what happens to variance of b1 - Answer variance to b1 gets
smaller
spread is what proportional to n - Answer spread is proportional to n
normal distribution - Answer N(mean, variance)
N(0,1) (CLT)
Why use Y bar to estimate uy - Answer Y bar is unbiased: E(Y bar) = uy
Y bar is consistent: Y bar --> uy
p
Y bar is the least squares estimator of uy (lecture slides 1 page 44)
