HW6_skeleton

7.2

• 1. standard normal distribution
• 2. alpha
• 3. .3085
• 4. .4027
• 1. Z=-2.45 area=.007

  2. Z=-.43 area=.3336

  3. Z= 1.35 area=.9115

  4. Z=3.49 area=.9998

• 1. Z=-3.01 area=.9987

  2. Z=-1.59 area=.9441

  3. Z=1.78 area=.0375

  4. Z=3.11 area=.0009

• 15. Z=.67
• 17. Z= -2.58 and Z= -2.57
• 23. Z= -2.14

shadenorm(mu=50, sig=7, above = 35,col = "blue",dens = 150)

• 24. Z=2.14

shadenorm(mu=50, sig=7, above = 65,col = "blue",dens = 150)

• 25. Z= -7.14

shadenorm(mu=50, sig=7, below = 45,col = "blue",dens = 150)

• 1. .8658

  2. .0132

  3. The proportion of the 18oz bag of Chips Ahoy Cookies that contains more than 1200 chocolate chips is .7019 or 70.19%

  4. .1230 or 12.30%

  5. 96th percentile

  6. 4th percentile

8.1

• 1. sampling distribution
• 2. mew, sigma/square root of n
• 3. standard error of the mean
• 4. True
• 5. False
• 6. False
• 7. The sampling is normal. The mean of the sampling distribution of x bar is mew sub x= mew= 30. The standard deviation is sigma sub x= sigma/square root of n= 8/the square root of 10(Need the shape, center and spread)
• 8. The sampling is normal. The mean of the sampling distribution of x bar is mew sub x=mew=50. The standard deviation is given by sigma sub x= sigma/square root of n= 4/square root of 40
• 9. mew sub x= mew= 80, sigma sub x=2
• 10. mew sub x= mew= 64, sigma sub x=3
• 1. Since mew=80 and sigma= 14, the mean and the standard deviation of the sampling distribution of x bar are given by mew sub x= mew= 80 and sigma sub x= 2. n=49 greater than or equal to 30 therefore by the Central Limit Thm. the sampling of x bar is approx. normal(Need the shape, center and spread)

  2. If we take 100 simple random size samples of size n=49 from a population with mew=80 and sigma=14 then about 7 of the samples will result in a mean that is greater than 83

  3. If we take 100 random samples of size n=49 from a population with mew=80 and sigma=14 then about 2 of the samples will have a mean less than or equal to 75.8

  4. If we take 100 simple random samples of size n=49 from a population with mew=80 and sigma=14 then about 78 of the samples will result in a mean that is between 78.3% and 85%.

• 1. If we select a simple random sample of n=100 human pregnancies then about 35 of the pregnancies would last less than 260 days

  2. The legnth of human pregnancies is normally distributed. The sampling distribution of x bar is normal. Mew sub x bar is 266 and sigma sub x is about 3.578.

  3. If we took 100 simple random samples of size n=20 human pregnancies, then about 5 of the samples will result in a mean gestation period of 260 days or less.

  4. If we rake 100 simple random samples of size n=50 human pregnancies then about 4 of the samples will result in a mean gestation period of 260 days or less

  5. It came from a population whose mean gestation period is less than 260 days.

  6. If we take 100 simple random samples of size n=15 human pregnancies then about 98 of the samples will result in a mean gestation period between 256 and 276 days.