Hypothesis Testing — Unit test Answers

A company has an opportunity to bid on three contracts. Determine which would be the best investment given the information in the table below.Probability of Profit and Loss by ContractContractProfit, Probability of ProfitProbability to Break EvenLoss, Probability of LossSoutheast$45,000, 50%30%$6,000, 20%Southwest$60,000, 35%40%$10,000, 25%California$112,000, 20%40%$40,000, 40%

A supervisor finds the mean number of miles that the employees in a department live from work. He finds and . Which statement must be true?

The distribution of the values of a population is shown below, and a simple random sample is drawn from the population. Based on this information alone, can the sample be used to make inferences about the population?

When finding the margin of error for the mean of a normally distributed population from a sample, what is , assuming a confidence level of 74%?

The times of all 15 year olds who run a certain race are approximately normally distributed with a given mean = 18 sec and standard deviation = 1.2 sec. What percentage of the runners have times less than 14.4 sec?

Mrs. Gomes found that 40% of students at her high school take chemistry. She randomly surveys 12 students. What is the probability that at most 4 students have taken chemistry? Round the answer to the nearest thousandth.

Car insurance companies want to keep track of the average cost per claim. The current data in use for Auto Insurance R Us is an average of $2,200 for each claim with a standard deviation of $500. With this average, the company can stay competitive with rates but not lose money. However, the statistician for the company believes that the cost of the average claim has increased. He pulled 40 recent claims and found the average to be $2,350. Which most restrictive level of significance would suggest that the company should raise rates? Upper-Tail Valuesa5%2.5%1%Critical z-values1.651.962.58

Which set of population data is the least dispersed from its mean?

The set of life spans of an appliance is normally distributed with a mean = 48 months and a standard deviation = 8 months. What is the life span of an appliance that has a z-score of –3?

When finding the margin of error for the mean of a normally distributed population from a sample, what is , assuming a confidence level of 74%?

A scientist calculated the mean and standard deviation of a data set to be and . She then found that she was missing one data value from the set. She knows that the missing data value was exactly 3 standard deviations away from the mean. What was the missing data value?

Vladimir rolls a six-sided number cube 36 times. If getting a 3 is a success, what is the probability of a success?

Derek Jeter challenges Albert Pujols to a batting battle. Each will earn 1 point for a hit other than a home run and 4 points for a home run in each round. Which player should you back given the statistics in the table below? Note that home runs are included as hits in the table.Data for Two BattersBatterAt BatsHitsHome RunsJeter4881569Pujols44812526

The grades of a science test are normally distributed. Thanh finds that his grade on the test has a z-score of –2.5. Which statement must be true?

A simple random sample of size n is drawn from a normally distributed population, and the mean of the sample is , while the standard deviation is s. What is the 90% confidence interval for the population mean? Use the table below to help you answer the question.Confidence Level90%95%99%z*-score1.6451.962.58