MATH 225N WEEK 8 STATISTICS QUIZ
COMPREHENSIVE EXAM SCRIPT 2026 SOLVED
QUESTIONS FULL SOLUTION
◉ In a sample of 15 stuffed animals, you find that they weigh an
average of 8.56 ounces with a sample standard deviation of 0.07
ounces. Find the 92% confidence interval, assuming the times are
normally distributed. Answer: (8.526, 8.594)
◉ Market research indicates that a new product has the potential to
make the company an additional $3.8 million, with a standard
deviation of $1.8 million. If this estimate was based on a sample of
10 customers from a normally distributed data set, what would be
the 90% confidence interval? Answer: (2.76, 4.84)
◉ Supplier claims that they are 95% confident that their products
will be in the interval of 20.45 to 21.05. You take samples and find
that the 95% confidence interval of what they are sending is 20.50
to 21.10. What conclusion can be made? Answer: The supplier
products have a higher mean than claimed
◉ In a sample of 15 small candles, the weight is found to be 3.72
ounces with a standard deviation of 0.963 ounces. What would be
, the 87% confidence interval for the size of the candles, assuming the
data are normally distributed? Answer: (3.320, 4.120)
◉ Answer: It would become wider due to the increased population
standard deviation
◉ A company claims that its heaters last more than 5 years. Write
the null and alternative hypotheses and note which is the claim.
Answer: Ho: μ ≤ 5, Ha: μ > 5 (claim)
◉ An executive claims that her employees spend no more than 2.5
hours each week in meetings. Write the null and alternative
hypotheses and note which is the claim. Answer: Ho: μ ≤ 2.5 (claim),
Ha: μ > 2.5
◉ n hypothesis testing, a key element in the structure of the
hypotheses is that the null hypothesis has the ________________________.
Answer: equality
◉ A landscaping company claims that at most 90% of workers arrive
on time. If a hypothesis test is performed that fails to reject the null
hypothesis, how would this decision be interpreted? Answer: There
is sufficient evidence to support the claim that at most 90% of
workers arrive on time
COMPREHENSIVE EXAM SCRIPT 2026 SOLVED
QUESTIONS FULL SOLUTION
◉ In a sample of 15 stuffed animals, you find that they weigh an
average of 8.56 ounces with a sample standard deviation of 0.07
ounces. Find the 92% confidence interval, assuming the times are
normally distributed. Answer: (8.526, 8.594)
◉ Market research indicates that a new product has the potential to
make the company an additional $3.8 million, with a standard
deviation of $1.8 million. If this estimate was based on a sample of
10 customers from a normally distributed data set, what would be
the 90% confidence interval? Answer: (2.76, 4.84)
◉ Supplier claims that they are 95% confident that their products
will be in the interval of 20.45 to 21.05. You take samples and find
that the 95% confidence interval of what they are sending is 20.50
to 21.10. What conclusion can be made? Answer: The supplier
products have a higher mean than claimed
◉ In a sample of 15 small candles, the weight is found to be 3.72
ounces with a standard deviation of 0.963 ounces. What would be
, the 87% confidence interval for the size of the candles, assuming the
data are normally distributed? Answer: (3.320, 4.120)
◉ Answer: It would become wider due to the increased population
standard deviation
◉ A company claims that its heaters last more than 5 years. Write
the null and alternative hypotheses and note which is the claim.
Answer: Ho: μ ≤ 5, Ha: μ > 5 (claim)
◉ An executive claims that her employees spend no more than 2.5
hours each week in meetings. Write the null and alternative
hypotheses and note which is the claim. Answer: Ho: μ ≤ 2.5 (claim),
Ha: μ > 2.5
◉ n hypothesis testing, a key element in the structure of the
hypotheses is that the null hypothesis has the ________________________.
Answer: equality
◉ A landscaping company claims that at most 90% of workers arrive
on time. If a hypothesis test is performed that fails to reject the null
hypothesis, how would this decision be interpreted? Answer: There
is sufficient evidence to support the claim that at most 90% of
workers arrive on time
