Practicing Normal Curve Calculations

The weights of paper discarded each week by households are normally distributed with a mean of 9.43 pounds and a standard deviation of 4.17 pounds.  What percent of households discard between 10 and 12 pounds? 

• 17.68%
• 6.50%
• 28.55%
• 82.32%

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CCSS.HSS.ID.A.4

The weights of paper discarded each week by households are normally distributed with a mean of 9.43 pounds and a standard deviation of 4.17 pounds.  What percent of households throw out fewer than 2 pounds of paper each week?

• 96.26%
• 48.13%
• 3.74%
• 1.87%

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CCSS.HSS.ID.A.4

The weights of paper discarded each week by households are normally distributed with a mean of 9.43 pounds and a standard deviation of 4.17 pounds.  How much paper do the top 10% of households discard? 

• 16.29 pounds
• 4.09 pounds
• 14.77 pounds
• 2.57 pounds

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CCSS.HSS.ID.A.4

A study of the amounts of time college freshmen study each week found that the times are normally distributed with a mean of 7.06 hours and a standard deviation of 2.32 hours.  How many hours would the "fastest" 5% of students spend on homework?

• 10.03 hours
• 10.86 hours
• 4.09 hours
• 3.24 hours

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CCSS.HSS.ID.A.4

Heights of women are normally distributed with a mean of 63.6 inches and a standard deviation of 2.5 inches.  The Beanstalk Club, a social organization for tall people, has a requirement that women must be at least 70 inches tall. What percentage of adult women meets the requirement to join the club?

• 0.52%
• 5%
• 99.48%
• 95%

Tags

CCSS.HSS.ID.A.4

Heights of women are normally distributed with a mean of 63.6 inches and a standard deviation of 2.5 inches.  The Beanstalk Club, a social organization for tall people, has a requirement that women must be at least 70 inches tall. What heights mark the middle 50% of all women?

• Those above 63.5 inches
• 61.1 inches to 66.1 inches
• 61.9 inches to 65.3 inches
• Those below 63.5 inches

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CCSS.HSS.ID.A.4

The lengths of human pregnancies are normally distributed with a mean of 268 days and a standard deviation of 15 days. What percent of pregnancies will last fewer than 8 months (approximately 240 days)? 

• 13.14%
• 96.9%
• 86.86%
• 3.10%

Tags

CCSS.HSS.ID.A.4

The lengths of human pregnancies are normally distributed with a mean of 268 days and a standard deviation of 15 days. How long is a pregnancy if it is considered one of the top 20% in length? 

• 280 days
• 255 days
• 249 days
• 287 days

Tags

CCSS.HSS.ID.A.4

The lengths of human pregnancies are normally distributed with a mean of 268 days and a standard deviation of 15 days.  What is the IQR for pregnancy length?

• 258 days
• 60 days
• 30 days
• 20 days

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CCSS.8.EE.C.8C

The ages of commercial aircraft are normally distributed.  If 10% of all aircraft have been in service for less than 2.88 years and 1% of all aircraft have been in service for more than 31.38 years, what are the mean and standard deviation of the age commercial aircraft?

• mean = 10 years and standard deviation = 4.5 years
• mean = 10 years and standard deviation = 9.8  years
• mean = 13 years and standard deviation = 7.9 years
• mean = 15 years and standard deviation is 5.5 years

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CCSS.8.EE.C.8C