ECON210 - Lesson 11: Hypothesis Tests

Read the z statistics from the normal distribution table and circle the correct answer. A two-tailed test at a .0694 level of significance; z =

-1.48 and 1.48

Read the z statistic from the normal distribution table and circle the correct answer. A one-tailed test (lower tail) at a .063 level of significance; z =

-1.53

Exhibit 9-6 A random sample of 100 people was taken. Eighty 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 75%. Refer to Exhibit 9-6. The p-value is

0.0156

Exhibit 9-2 The manager of a grocery store has taken a random sample of 100 customers. The average length of time it took the customers in the sample to check out was 3.1 minutes. The population standard deviation is known to be 0.5 minutes. We want to test to determine whether or not the mean waiting time of all customers is significantly more than 3 minutes. Refer to Exhibit 9-2. The p-value is

0.0228

Read the z statistic from the normal distribution table and circle the correct answer. A one-tailed test (upper tail) at a .123 level of significance; z =

1.16

Exhibit 9-6 A random sample of 100 people was taken. Eighty 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 75%. Refer to Exhibit 9-6. The test statistic is

1.25

Exhibit 9-2 The manager of a grocery store has taken a random sample of 100 customers. The average length of time it took the customers in the sample to check out was 3.1 minutes. The population standard deviation is known to be 0.5 minutes. We want to test to determine whether or not the mean waiting time of all customers is significantly more than 3 minutes. Refer to Exhibit 9-2. The test statistic is

2.00

A meteorologist stated that the average temperature during July in Chattanooga was 80 degrees. A sample of 32 Julys was taken. The correct set of hypotheses is

None of the answers are correct (H0: μ >= 80 Ha: μ < 80)

Exhibit 9-2 The manager of a grocery store has taken a random sample of 100 customers. The average length of time it took the customers in the sample to check out was 3.1 minutes. The population standard deviation is known to be 0.5 minutes. We want to test to determine whether or not the mean waiting time of all customers is significantly more than 3 minutes. Refer to Exhibit 9-2. At a .05 level of significance, it can be concluded that the mean of the population is

Significantly greater than 3

Exhibit 9-6 A random sample of 100 people was taken. Eighty 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 75%. Refer to Exhibit 9-6. At a .05 level of significance, it can be concluded that the proportion of the population in favor of candidate A is

Significantly greater than 75%

If a hypothesis test leads to the rejection of the null hypothesis, a

Type I error may have been committed

A Type II error is committed when

a true alternative hypothesis is mistakenly rejected

A Type I error is committed when

a true null hypothesis is rejected

As a general guideline, the research hypothesis should be stated as the

alternative hypothesis

For a two-tailed hypothesis test about m, we can use any of the following approaches except

compare the level of significance to the confidence coefficient

For a two-tailed hypothesis test about a population mean, the null hypothesis can be rejected if the confidence interval

does not include m 0

For a one-tailed test (upper tail) with a sample size of 900, the null hypothesis will be rejected at the .05 level of significance if the test statistic is

greater than or equal to 1.645

A two-tailed test is a

hypothesis test in which rejection region is in both tails of the sampling distribution

A one-tailed test is a

hypothesis test in which rejection region is in one tail of the sampling distribution

If a hypothesis test has a Type I error probability of .05, that means

if the null hypothesis is true, it will be rejected 5% of the time

If the cost of a Type I error is high, a smaller value should be chosen for the

level of significance

A p-value is the

probability, when the null hypothesis is true, of obtaining a sample result that is at least as unlikely as what is observed

A two-tailed test is performed at a 5% level of significance. The p-value is determined to be 0.09. The null hypothesis

should not be rejected

In hypothesis testing, the alternative hypothesis is

the hypothesis concluded to be true if the null hypothesis is rejected

For a sample size of 30, changing from using the standard normal distribution to using the t distribution in a hypothesis test,

will result in the rejection region being smaller