MATH 225N WEEK 6 DISCUSSION
CONFIDENCE INTERVAL BUNDLED TEST PAPER
2026 QUESTIONS WITH SOLUTIONS GRADED
A+
◉ point estimate. Answer: the value of that statistic from a sample;
"best guess" at the value of an unknown parameter
◉ the point estimator can be.... Answer: potential mean, standard
deviation, IQR, median, etc.
◉ The golf ball manufacturer would also like to investigate the
variability of the distance travelled by the golf balls by estimating
the interquartile range. What is the point estimate?. Answer: Use the
sample IQR as the point estimate for the true IQR
◉ The math department wants to know what proportion of its
students own a graphing calculator, so they take a random sample of
100 students and find that 28 own a graphing calculator. What is the
point estimator?. Answer: Use the sample proportion p-hat as the
point estimator for the true proportion p (the sample proportion is
0.28)
, ◉ confidence interval conditions. Answer: Random (SRS or
randomized experiment), Normal, Independent (10% rule)
◉ Normal conditions (CI): proportions. Answer: proportions: np and
n(1-p) must both be greater than/equal to 10
◉ Normal conditions (CI): means. Answer: means: the sampling
distribution is exactly normal if the population distribution is
normal. when the population distribution isn't normal, then the
Central Limit Theroem tells us the sampling distribution will be
approx. Normal if n is at least 30
◉ confidence interval formula (proportions). Answer:
◉ confidence interval formula (means). Answer:
◉ what are the z-scores for 99%, 95%, and 90% confidence
intervals?. Answer: 99%: 2.575
95%: 1.96
90%: 1.645
◉ confidence level. Answer: tells us how likely it is that the method
we're using will produce and interval that captures the population
parameter if we use it many times
CONFIDENCE INTERVAL BUNDLED TEST PAPER
2026 QUESTIONS WITH SOLUTIONS GRADED
A+
◉ point estimate. Answer: the value of that statistic from a sample;
"best guess" at the value of an unknown parameter
◉ the point estimator can be.... Answer: potential mean, standard
deviation, IQR, median, etc.
◉ The golf ball manufacturer would also like to investigate the
variability of the distance travelled by the golf balls by estimating
the interquartile range. What is the point estimate?. Answer: Use the
sample IQR as the point estimate for the true IQR
◉ The math department wants to know what proportion of its
students own a graphing calculator, so they take a random sample of
100 students and find that 28 own a graphing calculator. What is the
point estimator?. Answer: Use the sample proportion p-hat as the
point estimator for the true proportion p (the sample proportion is
0.28)
, ◉ confidence interval conditions. Answer: Random (SRS or
randomized experiment), Normal, Independent (10% rule)
◉ Normal conditions (CI): proportions. Answer: proportions: np and
n(1-p) must both be greater than/equal to 10
◉ Normal conditions (CI): means. Answer: means: the sampling
distribution is exactly normal if the population distribution is
normal. when the population distribution isn't normal, then the
Central Limit Theroem tells us the sampling distribution will be
approx. Normal if n is at least 30
◉ confidence interval formula (proportions). Answer:
◉ confidence interval formula (means). Answer:
◉ what are the z-scores for 99%, 95%, and 90% confidence
intervals?. Answer: 99%: 2.575
95%: 1.96
90%: 1.645
◉ confidence level. Answer: tells us how likely it is that the method
we're using will produce and interval that captures the population
parameter if we use it many times
