بنوتة البحرين
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- 21 أغسطس 2009
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السلام عليكم
اللي يدرس عند دكتور حاتم المصري ,, بغيت منكم حلول جبتر 2 اللي في موقعه www.hatemmasri.com .. حل سؤال رقم 7 و 8 و 9 اذا ماعليكم أمر ضروري ,,
7. Even before the record gas prices during the summer of 2008, an article written by Will Lester
of the Associated Press reported on a poll in which 80% of those surveyed say that Americans
who currently own a SUV (sport utility vehicle) should switch to a more fuel-efficient vehicle to
ease America’s dependency on foreign oil. This study was conducted by the Pew Research
Center for the People & the Press. As a follow-up to this report, a consumer group conducted a
study of SUV owners to estimate the mean mileage for their vehicles. A simple random sample
of 91 SUV owners was selected, and the owners were asked to report their highway mileage. The
following results were summarized from the sample data:
Based on these sample data, compute and interpret a 90% confidence interval estimate for the
mean highway mileage for SUVs.
8. According to USA Today, customers are not settling for automobiles straight off the
production lines. As an example, those who purchase a $355,000 Rolls-Royce typically add
$25,000 in accessories. One of the affordable automobiles to receive additions is BMW’s Mini
Cooper. A sample of 179 recent Mini purchasers yielded a sample mean of $5,000 above the
$20,200 base sticker price. Suppose the cost of accessories purchased for all Mini Coopers has a
standard deviation of $1,500.
a. Calculate a 95% confidence interval for the average cost of accessories on Mini Coopers.
b. Determine the margin of error in estimating the average cost of accessories on Mini Coopers.
c. What sample size would be required to reduce the margin of error by 50%?
9. The concession managers for the Arkansas Travelers (a minor league baseball team located in
Little Rock) are interested in estimating the average amount spent on food by fans attending the
team’s Friday night home games. Suppose a random sample of 36 receipts for food orders was
taken from last year’s receipts for Friday night home games with the following food expenditures
recorded:
a. Based on the sampled receipts, what is the best point estimate for the mean food expenditures
for Friday night home games?
b. Use the sample information to construct a 95% confidence interval estimate for the true mean
expenditures for Friday night home games.
c. Before the sample was taken, the food concessions manager stated that mean food
expenditures were about $19.00 per order. Does his statement seem consistent with the results
obtained in part b?
اللي يدرس عند دكتور حاتم المصري ,, بغيت منكم حلول جبتر 2 اللي في موقعه www.hatemmasri.com .. حل سؤال رقم 7 و 8 و 9 اذا ماعليكم أمر ضروري ,,
7. Even before the record gas prices during the summer of 2008, an article written by Will Lester
of the Associated Press reported on a poll in which 80% of those surveyed say that Americans
who currently own a SUV (sport utility vehicle) should switch to a more fuel-efficient vehicle to
ease America’s dependency on foreign oil. This study was conducted by the Pew Research
Center for the People & the Press. As a follow-up to this report, a consumer group conducted a
study of SUV owners to estimate the mean mileage for their vehicles. A simple random sample
of 91 SUV owners was selected, and the owners were asked to report their highway mileage. The
following results were summarized from the sample data:
Based on these sample data, compute and interpret a 90% confidence interval estimate for the
mean highway mileage for SUVs.
8. According to USA Today, customers are not settling for automobiles straight off the
production lines. As an example, those who purchase a $355,000 Rolls-Royce typically add
$25,000 in accessories. One of the affordable automobiles to receive additions is BMW’s Mini
Cooper. A sample of 179 recent Mini purchasers yielded a sample mean of $5,000 above the
$20,200 base sticker price. Suppose the cost of accessories purchased for all Mini Coopers has a
standard deviation of $1,500.
a. Calculate a 95% confidence interval for the average cost of accessories on Mini Coopers.
b. Determine the margin of error in estimating the average cost of accessories on Mini Coopers.
c. What sample size would be required to reduce the margin of error by 50%?
9. The concession managers for the Arkansas Travelers (a minor league baseball team located in
Little Rock) are interested in estimating the average amount spent on food by fans attending the
team’s Friday night home games. Suppose a random sample of 36 receipts for food orders was
taken from last year’s receipts for Friday night home games with the following food expenditures
recorded:
a. Based on the sampled receipts, what is the best point estimate for the mean food expenditures
for Friday night home games?
b. Use the sample information to construct a 95% confidence interval estimate for the true mean
expenditures for Friday night home games.
c. Before the sample was taken, the food concessions manager stated that mean food
expenditures were about $19.00 per order. Does his statement seem consistent with the results
obtained in part b?
التعديل الأخير:
