MATH 225N STATISTICS WEEK FOUR
CONTINGENCY TABLES EXAM SCRIPT 2026
COMPLETE QUESTIONS AND ANSWERS
GRADED A+
⩥ Many people think that a national lobby's successful fight against gun
control legislation is reflecting the will of a minority of Americans. A
random sample of 4000 citizens yielded 2250 who are in favor of gun
control legislation. Estimate the true proportion of all Americans who
are in favor of gun control legislation using a 90% confidence interval..
Answer: (0.5496, 0.5754)
⩥ Mamma Temte bakes six pies a day that cost $2 each to produce. On
25% of the days she sells only two pies. On 14% of the days, she sells 4
pies, and on the remaining 61% of the days, she sells all six pies. If
Mama Temte sells her pies for $5 each, what is her expected profit for a
day's worth of pies? [Assume that any leftover pies are given away and
therefore are counted as a loss.].
Answer: $11.60
⩥ Find the area under the standard normal curve between z = 1.5 and z =
2.5..
Answer: 0.0606
,⩥ A recent study attempted to estimate the proportion of Florida
residents who were willing to spend more tax dollars on protecting the
Florida beaches from environmental disasters. Thirty-two hundred
Florida residents were surveyed. Which of the following is the
population used in the study?.
Answer: all Florida residents
⩥ Find the area under the standard normal curve to the left of z = 1.25..
Answer: 0.8944
⩥ In a sample of 10 randomly selected employees, it was found that
their mean height was 63.4 inches. From previous studies, it is assumed
that the standard deviation, σ, is 2.4. Compute the 95% confidence
interval for μ..
Answer: (61.9, 64.9)
⩥ Identify the type of sampling used.
A writer for an art magazine randomly selects and interviews fifty male
and fifty female artists. What sampling technique is used?.
Answer: stratified
⩥ Provide an appropriate response.
, The percentage of measurements that are above the 63rd percentile is.
Answer: 37%
⩥ Provide an appropriate response.
The cell phone conversations of a random sample of 120 students has a
standard deviation of 9.7 minutes. Find the margin of error, E, using a
98% confidence interval..
Answer: 2.06
⩥ Provide an appropriate response.
Investing is a game of chance. Suppose there is a 38% chance that a
risky stock investment will end up in a total loss of your investment.
Because the rewards are so high, you decide to invest in four
independent risky stocks. Find the probability that at least one of your
four investments becomes a total loss. Round to the nearest ten-
thousandth when necessary..
Answer: 0.8522
⩥ Provide an appropriate response.
A pediatrician wants to determine the relation that exists between a
child's height, x, and head circumfrence, y. She randomly selects 11
CONTINGENCY TABLES EXAM SCRIPT 2026
COMPLETE QUESTIONS AND ANSWERS
GRADED A+
⩥ Many people think that a national lobby's successful fight against gun
control legislation is reflecting the will of a minority of Americans. A
random sample of 4000 citizens yielded 2250 who are in favor of gun
control legislation. Estimate the true proportion of all Americans who
are in favor of gun control legislation using a 90% confidence interval..
Answer: (0.5496, 0.5754)
⩥ Mamma Temte bakes six pies a day that cost $2 each to produce. On
25% of the days she sells only two pies. On 14% of the days, she sells 4
pies, and on the remaining 61% of the days, she sells all six pies. If
Mama Temte sells her pies for $5 each, what is her expected profit for a
day's worth of pies? [Assume that any leftover pies are given away and
therefore are counted as a loss.].
Answer: $11.60
⩥ Find the area under the standard normal curve between z = 1.5 and z =
2.5..
Answer: 0.0606
,⩥ A recent study attempted to estimate the proportion of Florida
residents who were willing to spend more tax dollars on protecting the
Florida beaches from environmental disasters. Thirty-two hundred
Florida residents were surveyed. Which of the following is the
population used in the study?.
Answer: all Florida residents
⩥ Find the area under the standard normal curve to the left of z = 1.25..
Answer: 0.8944
⩥ In a sample of 10 randomly selected employees, it was found that
their mean height was 63.4 inches. From previous studies, it is assumed
that the standard deviation, σ, is 2.4. Compute the 95% confidence
interval for μ..
Answer: (61.9, 64.9)
⩥ Identify the type of sampling used.
A writer for an art magazine randomly selects and interviews fifty male
and fifty female artists. What sampling technique is used?.
Answer: stratified
⩥ Provide an appropriate response.
, The percentage of measurements that are above the 63rd percentile is.
Answer: 37%
⩥ Provide an appropriate response.
The cell phone conversations of a random sample of 120 students has a
standard deviation of 9.7 minutes. Find the margin of error, E, using a
98% confidence interval..
Answer: 2.06
⩥ Provide an appropriate response.
Investing is a game of chance. Suppose there is a 38% chance that a
risky stock investment will end up in a total loss of your investment.
Because the rewards are so high, you decide to invest in four
independent risky stocks. Find the probability that at least one of your
four investments becomes a total loss. Round to the nearest ten-
thousandth when necessary..
Answer: 0.8522
⩥ Provide an appropriate response.
A pediatrician wants to determine the relation that exists between a
child's height, x, and head circumfrence, y. She randomly selects 11
