Q.4.1 A recent survey found that 35 people out of a sample of 410 South Africans suffer from diabetes. Construct a 95% confidence interval for the true proportion of all South Africans who suffer from diabetes. Interpret your answer.
Q.4.1 A recent survey found that 35 people out of a sample of 410 South Africans suffer
from diabetes. Construct a 95% confidence interval for the true proportion of all
South Africans who suffer from diabetes. Interpret your answer.
Q.4.2 The average age of a sample of 17 South African women who attend yoga classes
was found to be 31 years, with a standard deviation of 3.5 years. Construct a 90%
confidence interval for the true average age of all South African women who attend
yoga classes. Interpret your answer.
Q.4.3 The average time taken by a sample of 68 runners to complete a 10km race was 42
minutes. Assuming a population standard deviation of 8.65 minutes, construct a
99% confidence interval for the true average time taken by all runners to complete
the race. Interpret your answer.
Q.4.4 What two conditions will result in the use of the student-t distribution when
constructing a confidence interval for a population mean?
Q.4.5
Q.4.5.1 Explain briefly what is meant by the terms;
‘point estimate’
‘
Q.4.5.2 Why do statisticians prefer to use an interval estimate, rather than a point
estimate, when estimating the true value of a population parameter?
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