Give three advantages of sampling over a census

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Reference no: EM13687757

(a) Give three advantages of sampling over a census(b) The mean salary of accountants in Australia in May 2012 was $86,000, with a standard deviation of $20,000. A random sample of 400 accountant salaries is taken from around Australia. What is the (approximate) distribution of the sample mean salary? (c) An online survey conducted by a television station shows that 90% of respon- dents believe there will be tough economic conditions in the next five years. They conclude that this shows that 90% of Australians believe the same. Criticise with reasons the conclusion drawn from the survey. (d) A 95% confidence interval for a population mean based on a sample of size25 is (15.4, 25.6).(i) What is the value of the sample mean?(ii) The appropriate t-value used to compute the confidence interval is
2.0639. Calculate the value of the sample standard deviation
(e) A population proportion is required to be estimated to within 0.01 with 95%
confidence. What is the minimum sample size that is required?
(f ) In a simple linear regression analysis based on 30 observations, the fitted equation of regression is yˆ = -2.0x - 4.1. For this analysis,
SSY = 400 SSX = 81.
(i) Calculate the correlation coefficient between x and y.(g) An on-line music service company wants to know (for the purposes of de- signing a marketing campaign) if customer age is important in deciding to subscribe, and, if so, which age groups are most likely to subscribe to its service. The company has taken a random sample of 1000 people from the population, and asked each person whether he or she would subscribe to the service. A chi square test is conducted in Excel and the output is given below. Note that some of the entries have been deleted.(ii) Assuming the null hypothesis is true, find the value of the test statistic(iii) What is the (approximate) distribution of the test statistic assuming the null hypothesis is true? (Include the value(s) of any parameters.) (iv) Given that the p-value for the test is less than 0.000001, state the con- clusion of your hypothesis test at the 1% level of significance(v) Write a one sentence conclusion to the company manager informing her of your main finding regarding the age of the consumer and subscription to on-line music service

Reference no: EM13687757

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