Hypothesis Testing — Unit test Answers

For a standard normal distribution, find the approximate value of . Use the portion of the standard normal table below to help answer the question.zProbability0.000.50000.160.56360.220.58710.780.78231.000.84131.160.87701.780.96252.000.9772

The mean game scores and standard deviations of four seasons of a football team are given below.SeasonMeanStandard Deviation2005193.52006212.82007121.0200894.0Which statement must be true?

The human resources manager at a company records the length, in hours, of one shift at work, X. He creates the probability distribution below. What is the probability that a worker chosen at random works at least 8 hours?

The difference between an observational study and an experiment is that

The scores of the students on a standardized test are normally distributed, with a mean of 500 and a standard deviation of 110. What is the probability that a randomly selected student has a score between 350 and 550? Use the portion of the standard normal table below to help answer the question.zProbability0.000.50000.250.59870.350.63680.450.67361.000.84131.260.89611.350.91151.360.9131

Which normal distribution has the greatest standard deviation?

When finding the margin of error for the mean of a normally distributed population from a sample, what is the critical probability, assuming a confidence level of 58%?

When making a statistical inference about the mean of a normally distributed population based on a sample drawn from that population, which of the following statements is correct, all else being equal?

The graph below shows three different normal distributions.Which statement must be true?

The mean of a set of credit scores is and . Which statement must be true about z694?

To conduct a survey about the type of phone service most people in Greenville prefer, 10 different blocks in the neighborhood are chosen. On these 10 blocks, 10 houses are selected at random, and then each resident of each of those houses is interviewed. This type of sampling method is

Which of the following is a valid probability distribution?

The histogram below represents the number of points Mandy scored per game. The graph makes the data appear symmetric when it is actually skewed. How can the graph be adjusted to show the skew?

The hourly wages earned by 20 employees are shown in the first box-and-whisker plot below. The person earning $15 per hour quits and is replaced with a person earning $8 per hour. The graph of the resulting salaries is shown in plot 2.Plot 1 Plot 2 How does the mean and median change from plot 1 to plot 2?

A manager of a grocery store wants to determine if consumers are spending more than the national average. The national average is $150.00 with a standard deviation of $30.20. The manager collects 40 random receipts and finds that the average is $160. Complete a hypothesis test with a significance level of 2.5% to determine if the average customer spends more in his store than the national average. Which of the following is a valid conclusion for the manager based on this test?

In Juneau, Alaska, the 30-year annual snowfall average is 86.7 inches with a standard deviation of 40.4 inches. The last four years saw an average annual snowfall of 115.7 inches, 62.9 inches, 168.5 inches, and 135.7 inches. Hia performs a hypothesis test on this data to determine if the next 30-year norm will have a different average if the trend from the last four years continues. She uses a significance level of 5%. Which of the following is a conclusion that she may make?

A manager records the number of hours, X, each employee works on his or her shift and develops the probability distribution below. Fifty people work for the manager. How many people work 4 hours per shift?Probability DistributionHours Worked: XProbability: P(X)30.14?50.1460.370.3680.06

Destiny performs a hypothesis test on a population with µ = 115 and . Her sample size is 25 with a mean of 120.4. Which of the following correctly depicts the z-statistic for this data?

A high school student volunteers to present a report to the administration about the types of lunches students prefer. He surveys members of his class and records their choices. What type of sampling did the student use?

The annual salaries of all employees at a financial company are normally distributed with a mean = $34,000 and a standard deviation = $4,000. What is the z-score of a company employee who makes an annual salary of $28,000?