Many people struggle with gambling addictions. Gambling addicts can jeopardize their relationships with friends and family as they spiral into deeper and deeper debt. In order to quantify the degree of addiction a gambler suffers, a study surveyed a random sample of 100 gambling addicts. The amount of debt to be repaid is examined, and it is found that they have an average of 9 thousand dollars in gambling debts to repay. Suppose that all conditions are met and that the population standard deviation is o = 2.3 thousand dollars. In this problem, we will systematically investigate what happens to the length of the confidence interval as the sample size quadruples. (a) Calculate a 95% confidence interval for the mean amount of debt owed (in thousands of dollars) for all gambling addicts using the given sample size, n = 100. (Use a table or technology. Round your answers to three decimal places.) The 95% confidence interval based upon n = 100 is thousand dollars. (b) Calculate a 95% confidence interval for the mean amount of debt owed (in thousands of dollars) for all gambling addicts using the given sample size, n = 400. (Use a table or technology. Round your answers to three decimal places.) The 95% confidence interval based upon n = 400 is thousand dollars. (c) Calculate a 95% confidence interval for the mean amount of debt owed (in thousands of dollars) for all gambling addicts using the given sample size, n = 1,600. (Use a table or technology. Round your answers to three decimal places.) The 95% confidence interval based upon n = 1,600 is thousand dollars.

Borrowing money may be necessary for business expansion. However, too much borrowed money can also mean trouble. Are developing countries tending to borrow more? A random sample of 20 developing countries gave the following information regarding foreign debt per capita (in U.S. dollars, inflation adjusted). (Reference: Handbook of International Economic Statistics, U.S. Government Documents.) Country 1 2 3 4 5 6 7 8 9 10 Modern Debt per Capita 175 152 125 124 95 83 34 29 21 89 Historic Debt per Capita 147 134 86 113 58 62 33 36 49 72 Country 11 12 13 14 15 16 17 18 19 20 Modern Debt per Capita 23 28 18 29 197 189 144 124 102 71 Historic Debt per Capita 24 12 12 29 106 156 145 119 118 76 Does this information indicate that foreign debt per capita is increasing in developing countries? Use a 0.01 level of significance. (a) What is the level of significance? Compute the sample test statistic.   Find the P-value of the sample test statistic.

Practice question #3 Investigators want to know if those who work long hours have more trouble sleeping. In one sample of 190 British civil servants who worked more than 40 hours a week, 95 of them said they usually get less than 7 hours of sleep per night. In a second sample of 150 British civil servants who worked between 35 and 40 hours per week, 63 of them said they usually get less than 7 hours of sleep per night. The investigators believe these are represent samples of the populations. Find a 95% Confidence Interval for the difference in proportions of these two populations that get less than 7 hours of sleep per night. Then interpret the confidence interval. Be sure to check that any necessary conditions are met first. Round final answers to 3 decimal places. Verify conditions are appropriate for method: Interval: ________________________ Does the interval contain zero? __________ What does this information lead you to conclude?

Do single-parent families tend to be more impoverished than families with two parents? In order to test if there is a relationship between family structure and family income level, family researcher studied a sample of 35 one-parent and 65 two-parent families in a particular city to determine whether their total family income fell below the poverty level. _________________________Family Structure____________________________ Total family Income               One Parent                  Two Parents                TOTAL Below poverty level                      24                                      20                        44     Not Below Poverty Level                                            11                                      45                         56 Total                                            35                                      65                        100 What are the independent and dependent variables.? What is the null hypothesis? What test should we use?…

A company organizes its sales into territories, each assigned to one sales representative. An analyst theorizes that the on-the-job experience level of the sales rep may be related to the amount of sales in each territory. The analyst decided to use the time the sales reps had been employed at the company to predict sales. After taking a random sample of sales territories, the analyst measured the last quarter's Sales in dollars and the Experience the sales rep had at the company in months. Here are the three tables from the regression results: Regression Statistics Multiple R R Square Adjusted R Square Standard Error Observations ANOVA Regression Residual Total Intercept Experience (months) 0.5966 0.3559 0.339 497.9058 40 df 1 38 39 Coefficients 6.6108 SS 5205388.04 5205388.04 9420585.51 Standard Error 4250.9742 180.2332 14625973.55 1.4427 How many territories are in the sample? 247910.15 t Stat MS 23.586 4.5822 P-value 2.71E-24 4.85E-05 F 20.9971 Lower 95% Upper 95% 3886.1113…

Socially conscious investors screen out stocks of alcohol and tobacco makers, firms with poor environmental records, and companies with poor labor practices. Some examples of "good," socially conscious companies are Johnson and Johnson, Dell Computers, Bank of America, and Home Depot. The question is, are such stocks overpriced? One measure of value is the P/E, or price-to-earnings ratio. High P/E ratios may indicate a stock is overpriced. For the S&P Stock Index of all major stocks, the mean P/E ratio is ? = 19.4. A random sample of 36 "socially conscious" stocks gave a P/E ratio sample mean of x = 17.8, with sample standard deviation s = 5.8. Does this indicate that the mean P/E ratio of all socially conscious stocks is different (either way) from the mean P/E ratio of the S&P Stock Index? Use ? = 0.05.   I need help with sketching (d) and (e)

Philosophical and health issues are prompting an increasing number of Taiwanese to switch to a vegetarian lifestyle. A study published in the Journal of Nutrition compared the daily intake of nutrients by vegetarians and omnivores living in Taiwan. Among the nutrients considered was protein. Too little protein stunts growth and interferes with all bodily functions; too much protein puts a strain on the kidneys, can cause diarrhea and dehydration, and can leach calcium from bones and teeth. Independent random samples of 51 female vegetarians and 53 female omnivores yielded the following summary statistics, in grams, on daily protein intake. Vegetarians: X₁ = 39.04, s₁ = 18.82, n₁ = 51 Omnivores: X₂ = 49.92, S₂: 18.97, n₂ = 53 a. Do the data provide sufficient evidence to conclude that the mean daily protein intakes of female vegetarians and female omnivores differ? Perform the required hypothesis test at the 1% significance level. Assume equality of variances. b. Determine a 99%…

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Do single-parent families tend to be more impoverished than families with two parents? In order to test if there is a relationship between family structure and family income level, family researcher studied a sample of 35 one-parent and 65 two-parent families in a particular city to determine whether their total family income fell below the poverty level. _________________________Family Structure____________________________ Total family Income               One Parent                  Two Parents                TOTAL Below poverty level                      24                                      20                        44     Not Below Poverty Level                                            11                                      45                         56 Total                                            35                                      65                        100 What are the independent and dependent variables.? What is the null hypothesis? What test should we use?…