Chapter 9 Homework

Read the t statistic from the table of t distributions and circle the correct answer. A one-tailed test (lower tail), a sample size of 10 at a .10 level of significance; t=

-1.383

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 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

Exhibit 9-3 n=49 x=54.8 s=28 H0=50 Ha= <=50 Refer to Exhibit 9-3. The test statistic equals

1.2

Exhibit 9-1 n=36 x=24.6 s=12 H0: m <= 20 Ha: m > 20 Refer to Exhibit 9-1. The test statistic equals

2.3

The probability of making a Type 1 error is denoted by

Alpha (a)

A student believes that the average grade on the final examination in statistics is at least 85. She plans on taking a sample to test her belief. The correct set of hypotheses is

H0: m >= 85, Ha: m < 85

In hypothesis testing if the null hypothesis is rejected

None of the other answers are correct

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 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

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

alternative hypothesis

A one-tailed test is a

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

An example of statistical inference is

hypothesis testing

Two approaches to drawing a conclusion in a hypothesis test are

p-value and critical value

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

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 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%

More evidence against H0 is indicated by

smaller p-values