Reference no: EM132563165

Question 1:
A population of values has a normal distribution with iLt = 107.8 and o 82.8 . You intend to draw a random sample of size n = 203 .

Find the probability that a single randomly selected value is between 89.8 and 98.5. P(89.8 <X< 98.5) =

Find the probability that a sample of size n = 203 is randomly selected with a mean between 89.8 and 98.5.
P(89.8 <M< 98.5) =

Enter your answers as numbers accurate to 4 decimal places. Answers obtained using exact z-scores or z-scores rounded to 3 decimal places are accepted.

Question 2:
A population of values has a normal distribution with ou = 61.2 and o- = 21.9 . You intend to draw a random sample of size n = 74 .

Find P21, which is the mean separating the bottom 21% means from the top 79% means. P21 (for sample means) =

Enter your answers as numbers accurate to 1 decimal place. Answers obtained using exact z-scores or z-scores rounded to 3 decimal places are accepted.

Question 3:
A distribution of values is normal with a mean of 250 and a standard deviation of 16. From this distribution, you are drawing samples of size 32.

Find the interval containing the middle-most 30% of sample means:

Enter your answer using interval notation. In this context, either inclusive or exclusive intervals would be acceptable. Your numbers should be accurate to 1 decimal places. Answers obtained using exact z-scores or z-scores rounded to 3 decimal places are accepted.

Question 4:
Let X represent the full height of a certain species of tree. Assume that X has a normal probability distribution with mean 153.2 ft and standard deviation 92.2 ft.

You intend to measure a random sample of n = 205 trees. The bell curve below represents the distibution of these sample means. The scale on the horizontal axis is the standard error of the sampling distribution. Complete the indicated boxes, correct to two decimal places.

Question 5:
In a recent year, the Better Business Bureau settled 75% of complaints they received. (Source: USA Today, March 2, 2009) You have been hired by the Bureau to investigate complaints this year involving computer stores. You plan to select a random sample of complaints to estimate the proportion of complaints the Bureau is able to settle. Assume the population proportion of complaints settled for the computer stores is the 0.75, as mentioned above. Suppose your sample size is 186. What is the probability that the sample proportion will be within 3 percent of the population proportion?

Note: You should carefully round any z-values you calculate to 4 decimal places to match wamap's approach and calculations.

Question 6:
A Food Marketing Institute found that 25% of households spend more than $125 a week on groceries. Assume the population proportion is 0.25 and a simple random sample of 291 households is selected from the population. What is the probability that the sample proportion of households spending more than $125 a week is less than 0.22?

Note: You should carefully round any z-values you calculate to 4 decimal places to match wamap's approach and calculations.

Question 7:
A Food Marketing Institute found that 57% of households spend more than $125 a week on groceries. Assume the population proportion is 0.57 and a simple random sample of 103 households is selected from the population. What is the probability that the sample proportion of households spending more than $125 a week is more than than 0.49?

Note: You should carefully round any z-values you calculate to 4 decimal places to match wamap's approach and calculations.

Question 8:
A leading magazine (like Barron's) reported at one time that the average number of weeks an individual is unemployed is 36 weeks. Assume that for the population of all unemployed individuals the population mean length of unemployment is 36 weeks and that the population standard deviation is 3 weeks. Suppose you would like to select a random sample of 32 unemployed individuals for a follow-up study.

Find the probability that a single randomly selected value is less than 37. P(X < 37) =

Find the probability that a sample of size n = 32 is randomly selected with a mean less than 37. P(M< 37) =

Enter your answers as numbers accurate to 4 decimal places.

Question 9:
A leading magazine (like Barron's) reported at one time that the average number of weeks an individual is unemployed is 24 weeks. Assume that for the population of all unemployed individuals the population mean length of unemployment is 24 weeks and that the population standard deviation is 3.1 weeks. Suppose you would like to select a random sample of 63 unemployed individuals for a follow-up study.

Find the probability that a single randomly selected value is greater than 24.1.
P(X> 24.1) = (Enter your answers as numbers accurate to 4 decimal places.)
Find the probability that a sample of size n = 63 is randomly selected with a mean greater than 24 1
P(M> 24.1) = (Enter your answers as numbers accurate to 4 decimal places.)

Question 10:
A leading magazine (like Barron's) reported at one time that the average number of weeks an individual is unemployed is 14.8 weeks. Assume that for the population of all unemployed individuals the population mean length of unemployment is 14.8 weeks and that the population standard deviation is 9.5 weeks. Suppose you would like to select a random sample of 238 unemployed individuals for a follow-up study.
Find the probability that a single randomly selected value is between 13.8 and 16. P(13.8 <X< 16) =
Find the probability that a sample of size n =---- 238 is randomly selected with a mean between 13.8 and 16.
P(13.8 < M< 16) =
Enter your answers as numbers accurate to 4 decimal places.