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Confidence Interval

Critical value, confidence level

Please see the attached file. 1. What is the appropriate critical value for each of the following confidence levels and sample sizes? (Remember that in regard to confidence level this implies two-tails) (a) Critical z-value for an 85% confidence level for sample of size n = 36: (b) Critical t-value for

What is the corresponding confidence interval result of a hypothesis test?

Assume that in a hypothesis test with null hypothesis = 13.0 at 0.05, that a value of 11.0 for the sample mean results in the null hypothesis not being rejected. That corresponds to a confidence interval result of A. The 95% confidence interval for the mean does not contain the value 13.0 B. The 95% confidence interval for

Testing of Hypothesis and Confidence Interval.

Use the traditional method to test the given hypothesis. Assume that the population is normally distributed and that the sample has been randomly selected. 10) In one town, monthly incomes for men with college degrees are found to have a standard deviation of $650. Use a 0.01 significance level to test the claim that for men wi

Use the traditional method to test the given hypothesis.

Use the traditional method to test the given hypothesis. Assume that the samples are independent and that they have been randomly selected 11) In a random sample of 500 people aged 20 24, 22% were smokers. In a random sample of 450 people aged 25 29, 14% were smokers. Test the claim that the proportion of smokers inthe two age

Quantitative methods

The Whistle Stop Cafe in Weems, Georgia, is well known for it's popular homemade icecream. 12. For the demand data in Problem 11, develop a seasonally adjusted forecast for 2006. (Use a linear trend line model to develop a forecast estimate for 2006.) Which forecast model do you perceive to be accurate: the exponential smooth

Confidence Interval For Effect Of Birth Weight On IQ Score

Please help with the following. Confidence Interval for Effect of Birth Weight on IQ Score: When investigating a relationship between birth weight and IQ, researchers found that 258 subjects with extremely low birth weights (less than 1000 g) had Wechsler IQ scores at age 8 with a mean of 95.5 and a standard deviation of

Probability , hypothesis testing and confidence interval for a set of problems.

I would like help with the following exercises for future reference and a better overall understanding. Thanks! 1. The Los Angeles sheriff classifies crimes by age (in years) of the criminal and whether the crime is violent or nonviolent. As shown below, the sheriff reported a total of 150 crimes last year. Age (in years)

Confidence interval for proportion problem

Please help with the following problems involving confidence intervals. 1. Find the point estimate p-hat and the margin of error for the confidence interval (0.444, 0.484) 2 With destructive testing, sample items are destroyed in the process of testing them. Crash testing of cars is one very expensive example of destruct

Confidence interval for mean

Please see attached. If you can help me with the details of the nine attached questions...with detailed formulas and solutions, I really would appreciate it. 1. Of 139 adults selected randomly from one town, 30 of them smoke. a. Construct a 99% confidence interval for the true percentage of all adults in the town that

Estimation of the Population Proportion or Mean

Please see attached worksheet. If you can give me detailed formulas with answers it would be great. 1. The local Tupperware dealers earned these commissions last month: $4377.47 $3183.76 $1970.16 $2270.88 $3860.06 $2508.55 $1569.64 $4205.30 $1663.68 $3960.71 Assuming the population for the amount of commissions ea

Find the sample size needed for a 95% degree of confidence.

The weekly earnings of middle managers in a large corporation are approximately normally distributed with a standard deviation of 36 dollars. A researcher wishes to estimate the mean weekly earnings. Find the sample size needed if she requires a 95% degree of confidence that the sample mean will not differ from the population by

95% confidence interval & point estimate

I need help solving 95% confidence interval and point estimate problems. A sample of 16 people are used, each one is to keep track of their time with the following result in hours. 1.8, 1.7, 0.9, 1.1, 1.5, 1.5, 1.2, 0.6, 1.4, 0.9, 0.7, 1.8, 1.7, 2.2, 1.5, 1.3 Construct a 95% confidence interval for the amount of time n

You are in charge of selling advertising for radio station KGSM.

Always get overwhelmed by the amount of material when covered at a comprehensive level. Attached is the study material of what to be prepared to cover at the conclusion of this course. I have worked through them but get stumped at several points. Can you provide a systematic approach to these problems and provide a reference to

Confidence interval and t test for mean life time

Always get overwhelmed by the amount of material when covered at a comprehensive level. Attached is the study material of what to be prepared to cover at the conclusion of this course. I have worked through them but get stumped at several points. Can you provide a systematic approach to these problems and provide a reference to

Confidence Intervals and Hypothesis Testing

Please help with the following problem. Provide step by step calculations in Excel. 17. Consider a 98% confidence interval to estimate a population mean based on a sample of 625 observations with a sample mean of 425 and a sample standard deviation of 150. How many units wide would such a confidence interval be? 18. In a

Interpreting Results

Refer to the accompanying Minitab display of a 95% confidence interval generated using the methods of this section. The sample display results from using a random sample of speeds of drivers ticketed on a section of Interstate 95 in Connecticut. Variable N Mean StDev SE Mean 95% CI Speed

Minimum Sample Required in Statistics

1.) With a margin of error of 0.050; confidence level of 99% ^p and ^q unknown, what is the minimum sample size required to estimate a population proportion or percentage? 2.) Amounts lost by gamblers who took a bus to Atlantic City casino: 99% confidence; n=40, mean of values in sample = $189,standard deviation is known to b

Calculating Confidence Intervals

1. A study was conducted to estimate the mean amount spent on birthday gifts for a typical family having two children. A sample of 150 was taken, and the mean amount spent was $225. Assuming a standard deviation equal to $50, find the 95% confidence interval for mu, the mean for all such families. 2. A 95% confidence interv

True or False Questions about Statistics: If in a probability distribution you got the sum of probabilities less than one, it may mean that you skipped some possible outcome/outcomes.

TRUE OR FALSE (With justification)? If in a probability distribution you got the sum of probabilities less than one, it may mean that you skipped some possible outcome/outcomes. Health insurance policies are set up in such a way that a healthy person has a negative expected value, and a sickly person has a positive one.

Confidence interval estimate of the population total value

Please help with the following problem. A stationery store wants to estimate the total retail value of the 300 greeting cards that it has in its inventory. What are the upper and lower limits of the 95% confidence interval estimate of the population total value of all greeting cards that are in inventory if a random sample o

Confidence interval normal probability and Hypothesis testing problems

1) The length of time to do a complete full service oil change at Speedy-Lube, is normally distributed with a mean of 15.8 minutes and a standard deviation of 2.2 minutes. Refer to the following table. Table 5A Below normal distribution p(lower) p(upper) z x mean std.dev .0042 .9958 -2.64 10 15.8 2.2 .9719 .0281 1.91 20