Exam 12: Chi-Square and Nonparametric

SCENARIO 12-13 Recent studies have found that American children are more obese than in the past.The amount of time children spent watching television has received much of the blame.A survey of 100 ten-year- olds revealed the following with regards to weights and average number of hours a day spent watching television.We are interested in testing whether the mean number of hours spent watching TV and weights are independent at 1% level of significance. 12-30 Chi-Square and Nonparametric Tests -Referring to Scenario 12-13, if there is no connection between weights and average number of Hours spent watching TV, we should expect how many children to be spending no more than 6 Hours on average watching TV and are more than 10 lbs.underweight?

SCENARIO 12-4 A computer used by a 24-hour banking service is supposed to randomly assign each transaction to one of 5 memory locations.A check at the end of a day's transactions gave the counts shown in the table to each of the 5 memory locations, along with the number of reported errors. The bank manager wanted to test whether the proportion of errors in transactions assigned to each of the 5 memory locations differ. -Referring to Scenario 12-4, the critical value of the test statistic at 1% level of significance is

True or False: If we use the chi-square method of analysis to test for the difference between proportions, we must assume that there are at least 5 observed frequencies in each cell of the contingency table.

SCENARIO 12-13 Recent studies have found that American children are more obese than in the past.The amount of time children spent watching television has received much of the blame.A survey of 100 ten-year- olds revealed the following with regards to weights and average number of hours a day spent watching television.We are interested in testing whether the mean number of hours spent watching TV and weights are independent at 1% level of significance. 12-30 Chi-Square and Nonparametric Tests -Referring to Scenario 12-13, which of the following statements is correct?

SCENARIO 12-1 -Referring to Scenario 12-1, the company tests to determine at the 0.05 level whether the Population proportion has changed from the previous study.Which of the following is most Correct?

SCENARIO 12-13 Recent studies have found that American children are more obese than in the past.The amount of time children spent watching television has received much of the blame.A survey of 100 ten-year- olds revealed the following with regards to weights and average number of hours a day spent watching television.We are interested in testing whether the mean number of hours spent watching TV and weights are independent at 1% level of significance. 12-30 Chi-Square and Nonparametric Tests -Referring to Scenario 12-13, the value of the test statistic is

SCENARIO 12-10 -Referring to Scenario 12-10, a test was conducted to determine if a relationship exists between Defect rate and years of experience.Which of the following p-values would indicate that defect Rate and years of experience are dependent? Assume you are testing at = 0)05.

SCENARIO 12-11 The director of admissions at a state college is interested in seeing if admissions status (admitted, waiting list, denied admission)at his college is independent of the type of community in which an applicant resides.He takes a sample of recent admissions decisions and forms the following table: He will use this table to do a chi-square test of independence with a level of significance of 0.01. -True or False: Referring to Scenario 12-11, the p-value of this test is greater than 0.01.

If we use the method of analysis to test for the differences among 4 proportions, the degrees Of freedom are equal to:

SCENARIO 12-5 Four surgical procedures currently are used to install pacemakers.If the patient does not need to return for follow-up surgery, the operation is called a "clear" operation.A heart center wants to compare the proportion of clear operations for the 4 procedures, and collects the following numbers of patients from their own records: They will use this information to test for a difference among the proportion of clear operations using a chi-square test with a level of significance of 0.05. -True or False: Referring to Scenario 12-5, the null hypothesis will be rejected.

SCENARIO 12-1 -

True or False: A test for whether one proportion is higher than the other can be performed using the chi-square distribution.

SCENARIO 12-12 Parents complain that children read too few storybooks and watch too much television nowadays.A survey of 1,000 children reveals the following information on average time spent watching TV and average time spent reading storybooks -Referring to Scenario 12-12, if the null hypothesis of no connection between time spent Watching TV and time spent reading story books is true, how many children watching less than 2 Hours of TV and reading more than 2 hours of story books on average can we expect?

Scenario 12-6 According to an article in Marketing News, fewer checks are being written at the grocery store checkout than in the past.To determine whether there is a difference in the proportion of shoppers who pay by check among three consecutive years at a 0.05 level of significance, the results of a survey of 500 shoppers in three consecutive years are obtained and presented below. -True or False: Referring to Scenario 12-6, there is insufficient evidence to conclude that the proportions between year 1 and year 3 are different at a 0.05 level of significance.

SCENARIO 12-5 Four surgical procedures currently are used to install pacemakers.If the patient does not need to return for follow-up surgery, the operation is called a "clear" operation.A heart center wants to compare the proportion of clear operations for the 4 procedures, and collects the following numbers of patients from their own records: They will use this information to test for a difference among the proportion of clear operations using a chi-square test with a level of significance of 0.05. -True or False: Referring to Scenario 12-5, the decision made suggests that the 4 procedures all have different proportions of clear operations.

SCENARIO 12-12 Parents complain that children read too few storybooks and watch too much television nowadays.A survey of 1,000 children reveals the following information on average time spent watching TV and average time spent reading storybooks -Referring to Scenario 12-12, suppose we want to constrain the probability of committing a Type I error to 5% when testing whether there is any relationship between average time spent Watching TV and average time spent reading story books, the critical value will be

In testing for differences between the median of two independent populations, the null Hypothesis is

SCENARIO 12-8 -Referring to Scenario 12-8, the calculated test statistic is

SCENARIO 12-13 Recent studies have found that American children are more obese than in the past.The amount of time children spent watching television has received much of the blame.A survey of 100 ten-year- olds revealed the following with regards to weights and average number of hours a day spent watching television.We are interested in testing whether the mean number of hours spent watching TV and weights are independent at 1% level of significance. 12-30 Chi-Square and Nonparametric Tests -Referring to Scenario 12-13, how many children in the survey spend more than 6 hours Watching TV and are more than 10 lbs.overweight?

Scenario 12-6 According to an article in Marketing News, fewer checks are being written at the grocery store checkout than in the past.To determine whether there is a difference in the proportion of shoppers who pay by check among three consecutive years at a 0.05 level of significance, the results of a survey of 500 shoppers in three consecutive years are obtained and presented below. -True or False: Referring to Scenario 12-6, there is sufficient evidence to conclude that the proportions between year 1 and year 2 are different at a 0.05 level of significance.