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# Did some body knows about statistics

### Customer Question

Did some body knows about statistics?
Submitted: 8 years ago.
Category: Homework
Expert:  Manal Elkhoshkhany replied 8 years ago.

Hello and welcome to Just Answer

Please post your questions and I am sure someone will be able to help. It would also help if you quote your deadline as well as the name of the book you are using: title, author's name, and edition

Thank you

Customer: replied 8 years ago.
 Week 6: Two Sample Hypothesis Testing - HW_CONF_INTERVALS Help

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 1. Solve the problem.Given the same sample statistics, which level of confidence will produce the narrowest confidence interval? (Points: 1) 75% 85% 95% 90% 2. Solve the problem.The grade point averages for 10 randomly selected students in a statistics class with 125 students are listed below.What is the effect on the width of the confidence interval if the sample size is increased to 20? (Points: 1) The width decreases. The width remains the same. It is impossible to tell without more information. The width increases. 3. Solve the problem.Find the critical value zc that corresponds to a 98% confidence level. (Points: 1) ±1.645 ±1.96 ±2.575 ±2.33 4. Solve the problem.Determine the margin of error if the grade point averages for 10 randomly selected students from a class of 125 students has a mean of = 2.7. Assume the grade point average of the 125 students has a mean of = 2.9. (Points: 1) 0.2 2.6 -0.2 2.8 5. Solve the problem.A random sample of 40 students has a test score average with a standard deviation of 11.7. Find the margin of error if c = 0.98. (Points: 1) 1.81 1.85 4.31 0.68 6. Solve the problem.A random sample of 150 students has a grade point average with a mean of 2.86 and with a standard deviation of 0.78. Construct the confidence interval for the population mean, , if c = 0.98. (Points: 1) (2.71, 3.01) (2.51, 3.53) (2.31, 3.88) (2.43, 3.79) 7. Solve the problem.A group of 49 randomly selected students has a mean age of 22.4 years with a standard deviation of 3.8. Construct a 98% confidence interval for the population mean. (Points: 1) (20.3, 24.5) (21.1, 23.7) (19.8, 25.1) (18.8, 26.3) 8. Solve the problem.The standard IQ test has a mean of 100 and a standard deviation of 17. We want to be 99% certain that we are within 2 IQ points of the true mean. Determine the required sample size. (Points: 1) 1 580 480 22 9. Solve the problem.A survey of 400 non-fatal accidents showed that 152 involved the use of a cell phone. Find a point estimate for p, the population proportion of non-fatal accidents that involved the use of a cell phone. (Points: 1) 0.620 0.380 0.613 0.275 10. Solve the problem.A survey of 250 homeless persons showed that 37 were veterans. Find a point estimate p, for the population proportion of homeless persons who are veterans. (Points: 1) 0.174 0.852 0.148 0.129 11. Solve the problem.A survey of 300 fatal accidents showed that 123 were alcohol related. Construct a 98% confidence interval for the proportion of fatal accidents that were alcohol related. ENTER THE ANSWER IN THE FORMAT: (#.###, #.###) With an accuracy up to third decimal place.For example: (0.123, 0.321) (Points: 2) 12. Solve the problem.A survey of 280 homeless persons showed that 63 were veterans. Construct a 90% confidence interval for the proportion of homeless persons who are veterans. (Points: 1) (0.161, 0.289) (0.176, 0.274) (0.167, 0.283) (0.183, 0.266) 13. Solve the problem.A manufacturer of golf equipment wishes to estimate the number of left-handed golfers. How large a sample is needed in order to be 98% confident that the sample proportion will not differ from the true proportion by more than 5%? A previous study indicates that the proportion of left-handed golfers is 8%. (Points: 1) 174 41 160 114 14. Solve the problem.A researcher wishes to estimate the number of households with two cars. How large a sample is needed in order to be 90% confident that the sample proportion will not differ from the true proportion by more than 6%? A previous study indicates that the proportion of households with two cars is 23%. (Points: 1) 134 81 3 173

Customer: replied 8 years ago.
some body can tell me ! if you guys are available to help me or not with this i already put a deposit.....