Exam 9: One-Sample Tests of a Hypothesis

A manufacturer claims that less than 1% of all his products do not meet the minimum government standards. A survey of 500 products revealed ten did not meet the standard. If the computed value of z = -2.25 and the level of significance is 0.03, what is your decision?

Which of the following is NOT one of the five steps in the hypothesis testing procedure?

The mean weight of newborn infants at a community hospital is 6.6 pounds. A sample of seven infants is randomly selected and their weights at birth are recorded as 9.0, 7.3, 6.0, 8.8, 6.8, 8.4, and 6.6 pounds. Does this sample support the original claim? What is the decision for a significant increase in the average birthrate at a 5% level of significance?

i. An alternate hypothesis is a statement about a population parameter that is accepted when the null hypothesis is rejected. Ii) The level of significance is the risk we assume of rejecting the null hypothesis when it is actually true. Iii) There is only one level of significance that is applied to all studies involving sampling.

What are the critical z-values for a two-tailed hypothesis test if α = 0.01?

If α = 0.05 for a two-tailed test, how large is the acceptance area?

The average cost of tuition, room and board at community colleges is reported to be $8,500 per year, but a financial administrator believes that the average cost is higher. A study conducted using 150 community colleges showed that the average cost per year is $9,000 with a standard deviation of $1,200. Let α = 0.05. What is the critical z-value for this test?

The mean weight of newborn infants at a community hospital is 6.6 pounds. A sample of seven infants is randomly selected and their weights at birth are recorded as 9.0, 7.3, 6.0, 8.8, 6.8, 8.4, and 6.6 pounds. What is the sample standard deviation?

What is the critical value for a one-tailed hypothesis test in which a null hypothesis is tested at the 5% level of significance based on a sample size of 25?

The mean gross annual incomes of certified tack welders are normally distributed with the mean of $50,000 and a standard deviation of $4,000. The ship building association wishes to find out whether their tack welders earn more or less than $50,000 annually. The alternate hypothesis is that the mean is not $50,000. If the level of significance is 0.10, what is the decision rule?

Based on the Nielsen ratings, the local CBS affiliate claims its 11:00 PM newscast reaches 41% of the viewing audience in the area. In a survey of 100 viewers, 36% indicated that they watch the late evening news on this local CBS station. What is the null hypothesis?

Which of the following is a test statistic used to test a hypothesis about a population?

Based on the Nielsen ratings, the local CBS affiliate claims its 11:00 PM newscast reaches 41% of the viewing audience in the area. In a survey of 100 viewers, 36% indicated that they watch the late evening news on this local CBS station. What is the sample proportion?

The dean of a business school claims that the average starting salary of its graduates is more than $50,000. It is known that the population standard deviation is $10,000. Sample data on the starting salaries of 36 randomly selected recent graduates yielded a mean of $52,000. What is the value of the sample test statistic?

i. For a one-tailed test using the 0.05 level of significance, the critical value for the z test is 1.645, but for t it is 1.96. Ii) For a one-tailed test using the 0.01 level of significance, the critical value for the z-test is 1.645, but for t it is 1.96. Iii) For a two-tailed test using the 0.05 level of significance the critical value for the z-test is 1.96 and it is the same for the t-test.

i. If the null hypothesis is μ ≥ 200 and the alternate hypothesis states that μ is less than 200, then, a two-tail test is being conducted. Ii) For a one-tailed test of hypothesis, the area of rejection is only in one tail of the curve. Iii) As the sample size increases, the curve of the t-distribution approaches the standard normal distribution

The mean weight of newborn infants at a community hospital is 6.6 pounds. A sample of seven infants is randomly selected and their weights at birth are recorded as 9.0, 7.3, 6.0, 8.8, 6.8, 8.4, and 6.6 pounds. What is the sample mean?

The mean gross annual incomes of certified tack welders are normally distributed with the mean of $50,000 and a standard deviation of $4,000. The ship building association wishes to find out whether their tack welders earn more or less than $50,000 annually. The alternate hypothesis is that the mean is not $50,000. If the level of significance is 0.10, what is the critical value?

What is the probability of making a Type II error if the null hypothesis is actually true?

i. To set up a decision rule, the sampling distribution is divided into two regions-a region of non- rejection and a region where the null hypothesis is rejected. ii. A test statistic is a value determined from sample information collected to test the null hypothesis. iii. If the null hypothesis is true and the researchers do not reject it, then a correct decision has been made.