Question 1

To investigate the average amount spent each year on life insurance by individuals aged 50 or more, a random sample of 1,000 individuals over 50 is selected. The following results are calculated from the sample data (denoted by x): = 150 000 ( ) 2 = 1 249 080 a) Develop and interpret a 95% confidence interval for the population mean.

Question 2

In a survey of 1,250 voters in a constituency, 36% stated that they intended to vote for an independent candidate at the next election.

a)Develop and interpret a 90% confidence interval for the proportion of the population favouring an independent candidate.

b)What sample size would be required to estimate the proportion of the population favoring an independent candidate to be within 1% with 99% confidence?

Question 3

Maria a lady from Havana location in Windhoek, reported that her tuck shop makes an average daily income of N$400. Nadia argues that Maria's tuck shop makes more than what she's reported. Gerald visited his aunt Maria and recorded Maria's tuck shop daily income for ten days and found an average daily income of N$550 with a standard deviation of N$70. Required:

a)Use hypotheses test at a 1% level of significance and determine what conclusion can be reached about Maria's tuck shop's daily income.