In a test of weight loss programs, 40 adults used the Atkins weight loss program. After 12 months, their mean weight loss was found to be 2.1 lb., with a standard deviation of 4.8 lb. a. Construct a 95% confidence interval estimate of the mean weight loss for all subjects. Does the Atkins program appear to be effective? b. If a sample of 100 adults, construct a 95% confidence interval estimate of the mean weight loss for all subjects. Does the Atkins program appear to be effective? c. Based on the results on a) and b), explain the effect of sample size on the confidence interval estimate and its practical implication

An emergency planning administrator needs an estimate of the mean weight of relief vehicles when fully loaded. She selects a random sample of 500 trucks and finds a mean of 12.2 tons with a sample standard deviation of 2.9 tons. The width of the 95 percent confidence interval for the population mean is (enter the correct answer rounding to two significant digits (e.g. 3.14)) ?

Suppose a study was conducted of community colleges in California to determine the average cost of tuition for in-state students. The study consisted of 45 community colleges from California. Based on the sample data, the average tuition was $1,440 and the standard deviation was $267. Use this information to construct and interpret a 92% confidence interval for the true average tuition of all California community colleges. Make sure to check any relevant assumptions and state how you determined whether or not they were satisfied (Be as specific as possible). Make sure to type your confidence interval in an interval format with each bound rounded to 3 decimal places [i.e. (12.345, 45.678)]

In a survey, 19 people were asked how much they spent on their child's lost birthday gift. The results were roughly bellshaped with a mean of $46 and standard deviation of $8. Construct a confidence Interval at a 99% confidence level Give your answers to one decimal place:

A bank wishes to estimate the mean balances owed by customers holding MasterCard. The population standard deviation is estimated to be $500. If a 98 percent confidence interval is used and an interval of $80 is desired, how many cardholders should be sampled?

In a survey, 22 people were asked how much they spent on their child's last birthday gift. The results were roughly bell-shaped with a mean of $50 and standard deviation of $8. Construct a confidence interval at a 90% confidence level.Give your answers to one decimal place.

Choose the appropriate statistical test. When computing, be sure to round each answer as indicated. A dentist wonders if depression affects ratings of tooth pain. In the general population, using a scale of 1-10 with higher values indicating more pain, the average pain rating for patients with toothaches is 6.8. A sample of 30 patients that show high levels of depression have an average pain rating of 7.1 (variance 0.8). What should the dentist determine? 1. Calculate the estimated standard error. (round to 3 decimals). [st.error] 2. What is thet-obtained? (round to 3 decimals). 3. What is the t-cv? (exact value) 4. What is your conclusion? Only type "Reject" or Retain"

A researcher is studying the average cost of traveling for a college student. As part of their research, they would like to learn more about the average yearly money spent to travel to and from home by air. In a random sample of 130 students, the mean travel cost by air was $1180 with a standard deviation of $535. Use these sample data to answer the following questions.                                                                                                                                                                           Construct a 95% confidence interval to estimate the mean travel cost by air. Remember to include all relevant Minitab output and to identify your answer. You should not need to do any calculations by hand.

Q. No.4 The U.S. Dairy Industry wants to estimate the mean yearly milk consumption. A sample of 16 people reveals the mean yearly consumption to be 60 gallons with a standard deviation of 20 gallons. a. What is the value of the population mean? What is the best estimate of this value? b. Explain why we need to use the t distribution. What assumption do you need to make? c. For a 90 percent confidence interval, what is the value of t? d. Develop the 90 percent confidence interval for the population mean. e. Would it be reasonable to conclude that the population mean is 63 gallons?

ACT scores are normally distributed with mean 22 and standard deviation 4.7. A random sample of 32 MiSU students has a mean ACT of 23.6.  A. Estimate the mean ACT score for all MiSU students at the 95% confidence level. B. If we want to estimate the mean ACT score for all MiSU students at the 99% confidence level with a margin of error of 10, then what sample size will we need?