Lesson Review question Chapter 7 Hawkeslearning - MyMathLab Questions and Answers

Qn1. Trucks in a delivery fleet travel a mean of 120 miles per day with a standard deviation of 19 miles per day. The mileage per day is distributed normally. Find the probability that a truck drives less than 146 miles in a day. Round your answer to four decimal places.
Answer: - If you would like to look up the value in a table, select the table you want to view, then either click the cell at the intersection of the row and column or use the arrow keys to find the appropriate cell in the table and select it using the Space key.

Qn2. Find the value of z such that 0.13 of the area lies to the left of z. Round your answer to two decimal places.

Qn3. Find the value of z such that 0.03 of the area lies to the right of z. Round your answer to two decimal places.

Qn4. Calculate the standard score of the given X value, X=89.7, where μ=88.2 and σ=89.4 and indicate on the curve where z will be located. Round the standard score to two decimal places.

Qn5. Consider the probability that no fewer than 75 out of 109 students will not graduate on time. Assume the probability that a given student will not graduate on time is 98% .Specify whether the normal curve can be used as an approximation to the binomial probability by verifying the necessary conditions.

Qn6. Find the area under the standard normal curve between z=−0.75 and z=1.83. Round your answer to four decimal places, if necessary.

Qn7. Consider the probability that greater than 99 out of 159 flights will be on-time. Assume the probability that a given flight will be on-time is 61%. Approximate the probability using the normal distribution. Round your answer to four decimal places.

Qn8. The Arc Electronic Company had an income of 54 million dollars last year. Suppose the mean income of firms in the same industry as Arc for a year is 40 million dollars with a standard deviation of 9 million dollars. If incomes for this industry are distributed normally, what is the probability that a randomly selected firm will earn more than Arc did last year? Round your answer to four decimal places.

Qn9. Find the value of z such that 0.9722 of the area lies between −z and z. Round your answer to two decimal places.

Qn10. A soft drink machine outputs a mean of 28 ounces per cup. The machine's output is normally distributed with a standard deviation of 2 ounces. What is the probability of filling a cup between 30 and 31 ounces? Round your answer to four decimal places.

Qn11. Consider the probability that fewer than 38 out of 542 computers will crash in a day.
Choose the best description of the area under the normal curve that would be used to approximate binomial probability.

Qn12. A psychology professor assigns letter grades on a test according to the following scheme.
A: Top 13% of scores
B: Scores below the top 13% and above the bottom 57%
C: Scores below the top 43% and above the bottom 22%
D: Scores below the top 78% and above the bottom 8%
F: Bottom 8% of scores
Scores on the test are normally distributed with a mean of 71 and a standard deviation of 8.1. Find the numerical limits for a C grade. Round your answers to the nearest whole number, if necessary.

Hawkes Learning Chapter 8 Certification Chapter 8 Review Questions in Statistics

Qn1. direct mail company wishes to estimate the proportion of people on a large mailing list that will purchase a product. Suppose the true proportion is 0.07. If 402 are sampled, what is the probability that the sample proportion will be less than 0.04 ? Round your answer to four decimal places.

Qn2. Suppose a large shipment of laser printers contained 17% defectives. If a sample of size 224 is selected, what is the probability that the sample proportion will be greater than 16%? Round your answer to four decimal places.

Qn3. A carpet expert believes that 7% of Persian carpets are counterfeits. If the expert is accurate, what is the probability that the proportion of counterfeits in a sample of 574 Persian carpets would be less than 6%? Round your answer to four decimal places.

Qn4. The mean life of a television set is 138 months with a variance of 324. If a sample of 83 televisions is randomly selected, what is the probability that the sample mean would differ from the true mean by less than 5.4 months? Round your answer to four decimal places.

Qn5. A courier service company wishes to estimate the proportion of people in various states that will use its services. Suppose the true proportion is 0.07. If 330 are sampled, what is the probability that the sample proportion will differ from the population proportion by greater than 0.03? Round your answer to four decimal places.

Qn6 . If 330 are sampled, what is the probability that the sample proportion will differ from the population proportion by greater than 0.03? Round your answer to four decimal places.

Qn6. Suppose babies born in a large hospital have a mean weight of 3225 grams, and a standard deviation of 535 grams. If 106 babies are sampled at random from the hospital, what is the probability that the mean weight of the sample babies would differ from the population mean by more than 53 grams? Round your answer to four decimal places.

Qn7. Suppose 55% of the population has a college degree. If a random sample of size 496 is selected, what is the probability that the proportion of persons with a college degree will differ from the population proportion by less than 4%? Round your answer to four decimal places.

Qn8. The mean points obtained in an aptitude examination is 183 points with a standard deviation of 13 points. What is the probability that the mean of the sample would be greater than 186.2 points if 73 exams are sampled? Round your answer to four decimal places.

Qn9. Suppose cattle in a large herd have a mean weight of 1158lbs and a standard deviation of 92lbs. What is the probability that the mean weight of the sample of cows would be less than 1149lbs if 55 cows are sampled at random from the herd? Round your answer to four decimal places.

Qn10. Thompson and Thompson is a steel bolts manufacturing company. Their current steel bolts have a mean diameter of 135 millimeters, and a variance of 64. If a random sample of 32 steel bolts is selected, what is the probability that the sample mean would be less than 133 millimeters? Round your answer to four decimal places.