# Solved Assignment Library

Two business schools, A and B, located in the same metropolitan area and they are competing for bragging rights. One of the points of competition is average salary of graduating seniors. 30 graduating seniors from A and 25 from B were surveyed. A’s students had an average salary of \$62,000, and B's students had an average salary of \$67,000. Based on historical data, the population standard deviation is assumed to be \$10,000 for A and \$15,000 for B. Construct the hypotheses and conduct the appropriate tests that school B could use to claim that its students have a higher average graduating salary that A. Using a 5% level of significance, and the sample data provided, determine if school B can claim that its average graduating salary is greater than that of school A.
A researcher claims that average body temperature is different for the two genders. A sample of 65 men and 65 women yields average body temperatures of 98.105 and 98.394 oF, respectively. Based on historical data, the standard deviation of body temperature is known to be 0.699 and 0.743 degrees Fahrenheit, respectively. At a 5% level of significance, can you conclude that average body temperature differs with gender? Would your answer change for a 1% level of significance?
The table below summarizes results from a study of people who refused to answer survey questions. Use the table to answer the following questions. Be very careful to read the question carefully to determine whether or not there is overlap. Age  18-21  22-29   30-39  40-49  50-59  60 and over Responded  70  252  242  133  135  199 Refused  13  22  35  28  37  59 If one of the subjects is randomly selected, what is the probability that a randomly selected person is between 22 and 29 years or refused to answer? The probability that a randomly selected person is between 22 and 29 years or refused to answer is _____ (Do not round until the final answer. Then round to three decimal places as needed. If one of the subjects is randomly selected, what is the probability that the selected person was between 16 and 21 years or refused to answer? The probability that the selected person was between 18
The lengths of paper clips produced by a factory are normally distributed with a mean of 2.52 cm and a standard deviation of 0.08 cm. (a) What is the probability that a paper clip selected at random will have a length more than 2.55 cm? (b) If 3% of the paper clips produced had a length of more than k cm, find the value of k.
Data of smokers and cancer prevalence                             Cancer No Cancer Does not Smoke 10 100 Smokes Occassionally 50 50 Smokes regularly 100 5   a) What is the probability of a person having cancer and does not smoke? b) What is the probability that the person has cancer given he/she smokes regularly? c) What is the probability of a person does not smokes and and has no cancer?
The phone lines to an airline reservation system are occupied 50% of the time. Assume that the events that the lines are occupied on successive calls are independent. Assume that 10 calls are placed to the airline. (a) What is the probability that for exactly three calls the lines are occupied? (b) What is the probability that for at least one call the lines are not occupied? (c) What is the expected number of calls in which the lines are all occupied?
A town recently dismissed 7 employees in order to meet their new budget reductions. The town had 8 employees over 50 years of age and 16 under 50. If the dismissed employees were selected at random, what is the probability that no employees were over 50? Express your answer as a fraction or a decimal number rounded to four decimal places.
The computer that controls a bank's automatic teller machine crashes a mean of 0.4 times per day. What is the probability that, in any seven-day week, the computer will crash less than 2 times? Round your answer to four decimal places.
A well-mixed cookie dough will produce cookies with a mean of 8 chocolate chips apiece. What is the probability of getting a cookie with at least 4 chips?
The number of calls received by an office on Monday morning between 8:00 AM and 9:00 AM has a mean of 4. Calculate the probability of getting no more than 5 calls between eight and nine in the morning. Round your answer to four decimal places.