Questions: Please type inThe Gallup organization produced a surveyabout how much

Question

Questions: Please type inThe Gallup organization produced a surveyabout how much money people expected to spend on holiday presentsin 2003. The sample mean of the 82 responses was 857dollars.
g) Suppose that for these expected shopping expenditures thepopulation standard deviation is = 250. Calculatethe standard deviation of the sampling distribution of the samplemean.
h) Calculate a 98% confidence interval for the population mean.Show your calculations!!

i) How would you explain this confidence interval to someone whoknows no statistics? (ie, what does it mean??)
j) How many people would you need to sample to estimate the amountspent on presents to within $25, with 95% confidence?

k) What is a reasonable substitute for that is actuallyknown, and can be calculated from sample data?

Explanation / Answer

Questions: Please type inThe Gallup organization produced a surveyabout how much money people expected to spend on holiday presentsin 2003. The sample mean of the 82 responses was 857dollars. g) Suppose that for these expected shopping expenditures thepopulation standard deviation is ? = 250. Calculate thestandard deviation of the sampling distribution of the samplemean. /(n) = 250/(82) = 27.61 h) Calculate a 98% confidence interval for the population mean.Show your calculations!! ME = 2.33*27.61 = 64 ==> 857±64 = (793, 921) i) How would you explain this confidence interval to someone whoknows no statistics? (ie, what does it mean??) WE ARE 98% CONFIDENT THE POPULATION MEAN IS BETWEEN $793 and$921. j) How many people would you need to sample to estimate the amountspent on presents to within $25, with 95% confidence? 25 = 1.96*250/(n) ==> n = 384.16, so use 385 to besafe k) What is a reasonable substitute for ? that is actually known,and can be calculated from sample data? SAMPLE STANDARD DEVIATION

Related Questions

Navigate

• Browse (All)
• Browse Q
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.