Exam 9: Hypothesis Tests

In the last presidential election, a national survey company claimed that no more than 50% i.e., ≤ 50%) of all registered voters voted for the Republican candidate. In a random sample of 400 registered voters, 208 voted for the Republican candidate. a. State the null and the alternative hypotheses. b. Compute the test statistic. c. At 95% confidence, compute the p-value and test the hypotheses.

The level of significance in hypothesis testing is the probability of

When the following hypotheses are being tested at a level of significance of α H0: μ ≥ 500 Ha: μ < 500 The null hypothesis will be rejected if the p-value is

Last year, a soft drink manufacturer had 21% of the market. In order to increase their portion of the market, the manufacturer has introduced a new flavor in their soft drinks. A sample of 400 individuals participated in the taste test and 100 indicated that they like the taste. We are interested in determining if more than 21% of the population will like the new soft drink. a. Set up the null and the alternative hypotheses. b. Determine the test statistic. c. Determine the p-value. d. At 95% confidence, test to determine if more than 21% of the population will like the new soft drink.

Your investment executive claims that the average yearly rate of return on the stocks she recommends is at least 10.0%. You plan on taking a sample to test her claim. The correct set of hypotheses is

Exhibit 9-5 A random sample of 100 people was taken. Eighty-five of the people in the sample favored Candidate A. We are interested in determining whether or not the proportion of the population in favor of Candidate A is significantly more than 80%. -Refer to Exhibit 9-5. The p-value is

The manager of an automobile dealership is considering a new bonus plan in order to increase sales. Currently, the mean sales rate per salesperson is five automobiles per month. The correct set of hypotheses for testing the effect of the bonus plan is

The school's newspaper reported that the proportion of students majoring in business is at least 30%. You plan on taking a sample to test the newspaper's claim. The correct set of hypotheses is

In hypothesis testing if the null hypothesis is rejected,

Ahmadi, Inc. has been manufacturing small automobiles that have averaged 50 miles per gallon of gasoline in highway driving. The company has developed a more efficient engine for its small cars and now advertises that its new small cars average more than 50 miles per gallon in highway driving. An independent testing service road- tested 64 of the automobiles. The sample showed an average of 51.5 miles per gallon with a standard deviation of 4 miles per gallon. a. Formulate the hypotheses to determine whether or not the manufacturer's advertising campaign is legitimate. b. Compute the test statistic. c. What is the p-value associated with the sample results and what is your conclusion? Let α = .05.

You are given the following information obtained from a random sample of 4 observations. 25 47 32 56 You want to determine whether or not the mean of the population from which this sample was taken is significantly different from 48. Assume the population is normally distributed.) a. State the null and the alternative hypotheses. b. Determine the test statistic. c. Determine the p-value; and at 95% confidence test to determine whether or not the mean of the population is significantly different from 48.

The power curve provides the probability of

If a hypothesis is not rejected at the 5% level of significance, it

The average hourly wage of computer programmers with 2 years of experience has been $21.80. Because of high demand for computer programmers, it is believed there has been a significant increase in the average wage of computer programmers. To test whether or not there has been an increase, the correct hypotheses to be tested are

A law enforcement agent believes that at least 88% of the drivers stopped on Saturday nights for speeding are under the influence of alcohol. A sample of 66 drivers who were stopped for speeding on a Saturday night was taken. Eighty percent of the drivers in the sample were under the influence of alcohol. a. State the null and alternative hypotheses. b. Compute the test statistic. c. Using the p-value approach, test the hypotheses at the .05 level of significance.

In the hypothesis testing procedure, α is

The average monthly rent for one-bedroom apartments in Chattanooga has been $700. Because of the downturn in the real estate market, it is believed that there has been a decrease in the average rental. The correct hypotheses to be tested are

Nancy believes that the average running time of movies is equal to 140 minutes. A sample of 4 movies was taken and the following running times were obtained. Assume the population of the running times is normally distributed. 150 150 180 170 a. Compute the sample mean and the standard deviation. b. State the null and alternative hypotheses. c. Using the critical value approach, test the hypotheses at the 10% level of significance. d. Using the p-value approach, test the hypotheses at the 10% level of significance.

An automobile manufacturer stated that it will be willing to mass produce electric-powered cars if more than 30% of potential buyers indicate they will purchase the newly designed electric cars. In a sample of 500 potential buyers, 160 indicated that they would buy such a product. a. State the hypotheses for this problem b. Compute the standard error of . c. Compute the test statistic. d. At 95% confidence, what is your conclusion? Should the manufacturer produce the new electric powered car?

Exhibit 9-1 =36 =24.6 =12 :\mu\leq20 :\mu>20 -Refer to Exhibit 9-1. If the test is done at 95% confidence, the null hypothesis should